Practical tasks in physics oge. Determination of the coefficient of sliding friction. Determination of the optical power of a converging lens
The structure of the CMM variant provides verification of all providedFederal component of the state educational standard
activities: assimilation of the conceptual apparatus of the basic physics course
schools, mastering methodological knowledge and experimental
skills, the use of texts in the performance of educational tasks
physical content, application of knowledge in solving computational problems
and explanation of physical phenomena and processes in situations of a practice-oriented nature.
Possession of the basics of knowledge about the methods of scientific knowledge and
experimental skills are tested in tasks 18, 19 and 23.
Tasks 18 and 19 control the following skills:
- formulate (distinguish) the objectives of the conduct (hypothesis, conclusions)
described experience or observation;
– design an experimental setup, choose the order
conducting the experiment in accordance with the proposed hypothesis;
– use physical instruments and measuring instruments
for direct measurements of physical quantities;
– to analyze the results of experimental studies, in
including those expressed in the form of a table or graph.
Experimental tasks #23
Experimental skills are tested by tasksthree types:
1) assignments for indirect measurements of physical quantities;
2) tasks that test the ability to represent
graphs and draw conclusions based on the obtained
experimental data;
3) tasks that test the ability to conduct
experimental verification of physical laws;
Criteria for assessing the performance of task No. 23
Completely correct performance of the task is assessed 4points, for this you need:
1) schematic drawing of the experimental setup;
2) a formula for calculating the desired value for available for
measurement quantities;
3) correctly recorded results of direct measurements
(physical quantities are indicated, direct measurements
which need to be carried out in this task);
4) the correct numerical value of the desired
quantities.
List of equipment kits
List of equipment sets for carrying outexperimental tasks is compiled on the basis of typical
sets for frontal work in physics.
Set #1
lever scales with a set of weights
measuring cylinder (beaker) with
measuring limit 100 ml, C = 1 ml
glass of water
steel cylinder on thread
threaded brass cylinder
V = 20 cm3, m = 170 g, designate No. 2
Set №2
limit dynamometer
4 N (C = 0.1 N)
glass of water
steel cylinder on thread
V = 20 cm3, m = 156 g, designate No. 1
threaded brass cylinder
V = 20 cm3, m = 170 g, designate No. 2 Set №3
tripod laboratory with clutch and
paw
spring hardness (40±1) N/m
measurements 4 N (C = 0.1 N)
ruler 200–300 mm long with
millimeter divisions
Set №5
voltmeter 0–6 V, C = 0.2 V
ammeter 0–2 A, C = 0.1 A
variable resistor (rheostat),
resistance 10 ohm
resistor, R1 = 12 ohm, designate R1
resistor, R2 = 6 ohm, designate R2
connecting wires, 8 pcs.
key
working field
Set №4
carriage with a hook on a thread m = 100 g
three loads weighing (100±2) g
school dynamometer with limit
measurements 4 N (C = 0.1 N)
guide (coefficient
carriage friction along the guide
approximately 0.2)
Set №6
converging lens, focal length
F1 = 60 mm, designate L1
ruler 200–300 mm long with
millimeter divisions
screen
working field
4.5V DC power supply
connecting wires
key
stand lamp Set №7
tripod with clutch and foot
meter ruler (error 5 mm)
ball with attached to it
thread 110 cm long
clock with second hand (or stopwatch)
Set No. 8
tripod with clutch
lever arm
movable block
block fixed
a thread
three loads weighing (100±2) g
school dynamometer with a measurement limit of 4 N (C = 0.1 N)
ruler 200–300 mm long with millimeter divisions
Experimental tasks of the 1st type
The purpose of the task: testing the ability to make indirect measurementsphysical quantities.
Suggested work:
1. density of matter,
2. the forces of Archimedes,
3.coefficient of sliding friction,
4.spring stiffness,
5.period and frequency of oscillation of the mathematical pendulum,
6.moment of force acting on the lever,
7.The work of the elastic force when lifting the load using a movable or fixed block,
8.work friction force,
9.optical power of converging lens,
10.
resistor electrical resistance,
11.
work of electric current,
12.
Determination of the density of a substance
Use kit #1Using a balance scale with
weight, beaker, glass of water,
cylinder number 2, assemble
measuring the density of the material, from
which cylinder No. 2 was made.
On the answer sheet:
1) make a drawing
experimental setup
to determine the volume of the body;
density;
the mass of the cylinder and its volume;
density of the material of the cylinder.
Example of a possible solution
setting the density of the substance from which it is made
the cylinder turned out to be equal to 8500 kg / m 3.
10. Determination of the strength of Archimedes
Use kit #2Using a dynamometer, a glass with
water, cylinder number 1, collect
experimental setup for
buoyancy definitions
(force of Archimedes) acting on
cylinder.
On the answer sheet:
1) make a drawing
experimental setup;
2) write down the formula for calculation
buoyant force;
the weight of the cylinder in the air and the weight
cylinder in water;
buoyant force.
Example of a possible solution
1) Scheme of the experimental setup
Output: In progress
pilot task force
Archimedes turned out to be equal to 0.2 N.
11. Determination of the coefficient of sliding friction
Use kit #4Using a carriage (bar) with
crochet, dynamometer, one load,
guide rail, assemble
experimental setup for
friction coefficient measurements
sliding between the carriage and
rail surface.
On the answer sheet:
1) make a drawing
experimental setup;
2) write down the formula for calculation
coefficient of sliding friction;
3) indicate the measurement results
carriage weight with load and force
slats;
4) write down the numerical value
coefficient of sliding friction.
Example of a possible solution
1) Scheme of the experimental setup
Output: In progress
experimental setting coefficient
sliding friction was found to be 0.2.
12. Determination of the moment of force acting on the lever
Use kit #8Using a lever, three weights, a tripod and
dynamometer, assemble the installation for
studies of lever balance. Three loads
hang to the left of the axis of rotation of the lever
as follows: two loads per
distance 6 cm and one load at a distance
12 cm from the axis. Determine the moment of force
to be applied to the right
the end of the lever at a distance of 12 cm from the axis
rotation of the lever in order to
remained in balance in the horizontal
position.
On the answer sheet:
1) draw a diagram of the experimental
installations;
2) write down the formula for calculating the moment
strength;
3) indicate the measurement results
applied force and arm length;
4) write down the numerical value of the moment
strength.
Example of a possible solution
1) Scheme of the experimental setup
2) M=Fl
3) F = 2H, l = 0.12 m
4) M = 2N 0.12 m = 0.3 N m
Output: In progress
experimental task moment
force to be applied
to the right end of the lever was
equal to 0.3 N m.
13. Determining the stiffness of the spring
Use kit #3Using a tripod with a clutch and foot,
spring, dynamometer, ruler and two
cargo, assemble the experimental
hardness measuring station
springs. Determine the hardness
springs by hanging two weights from it.
To measure the weight of goods
use a dynamometer.
On the answer sheet:
1) Make a drawing
experimental setup;
2) write down the formula for calculation
spring stiffness;
3) indicate the measurement results
the weight of the loads and the elongation of the spring;
4) write down the numerical value
spring stiffness.
Example of a possible solution
1) Scheme of the experimental setup
Output: In progress
experimental task
the stiffness factor turned out to be
equal to 40 N/m.
14. Determination of the period and frequency of oscillations of a mathematical pendulum
Use kit #7determining the period and frequency of free
oscillations of a thread pendulum.
On the answer sheet:
installations;
2) Give the formula for calculating the period and
oscillation frequency;
3) indicate the results of direct measurements of the number
oscillation and oscillation time for lengths
pendulum threads equal to 0.5 m;
4) calculate the period and frequency of oscillation;
Example of a possible solution
1) Scheme of the experimental setup
2) T = t/N; v = 1/T;
3) N = 30; t = 42 s.
4) T \u003d t / N \u003d 1.4 s; ν \u003d 1 / T \u003d 0.7 Hz.
Output: In progress
experimental task period
free oscillations turned out to be equal to 1.4 s,
frequency 0.7 Hz.
15. Determination of the work of the friction force
Use kit #4Using a carriage (bar) with a hook,
dynamometer, one weight, guide
rail,
collect
experimental
installation for determining the work of force
friction when moving in a horizontal
the direction of the carriage with the load on the length
slats.
On the answer sheet:
installations;
2) write down the formula for calculating work
friction forces;
3) indicate the results of force measurements
sliding friction in motion
surface loaded carriages
rails, rail lengths;
4) write down the numerical value. work
friction forces.
Example of a possible solution
1) Scheme of the experimental
2) A=F s; Ftr = Fthrust (when
uniform motion)
tr
installations
3) Fthrust = 0.4 N; l = 0.5 m;
4) A \u003d 0.4 N 0.5 m \u003d 2 J.
Output: In progress
sliding friction turned out to be equal to
2 J
16. Determination of the electrical resistance of a resistor
Use kit #5Determine the electrical
resistor R1. For
assemble the experimental
installation using a power source
4.5V, voltmeter, ammeter, key,
rheostat, connecting wires and
resistor, labeled R1. At
using a rheostat, install in the circuit
current strength 0.2 A.
On the answer sheet:
experiment;
2) write down the formula for calculation
electrical resistance;
3) indicate the measurement results
voltage at a current of 0.2 A;
4) write down the numerical value
electrical resistance.
Example of a possible solution
1) Scheme of the experimental
installations
Output: In progress
experimental task
the resistance of the resistor R1 turned out to be
equal to 12 ohms.
17. Determination of current power
Use kit #5designated
R2,
collect
experimental setup for
determining the power allocated
on a resistor at a current strength of 0.5 A.
On the answer sheet:
1) draw the electrical circuit
experiment;
2) write down the formula for calculation
power of electric current;
3) indicate the measurement results
voltage at a current of 0.5 A;
4) write down the numerical value
power of electric current.
Example of a possible solution
1) Scheme of the experimental
installations
Output: In progress
experimental setting power
electric current was equal to 1.5 watts.
18. Determination of the work of the elastic force when lifting a load using a movable block
Use kit #8movable, thread, 3 weights,
determine the work of the elastic force
when lifting three loads to a height
20 cm
On the answer sheet:
1) make a drawing
experimental setup;
2) give a formula for calculating
the work of the elastic force;
3) indicate the results of direct
height and strength measurements
elasticity;
4) Calculate the work of the force
elasticity when lifting three
cargo to the specified height;
Example of a possible solution
1) Scheme of the experimental setup
2) A = Fcontrol.h;
3) F ex. \u003d 2 N (with uniform
movement);
h = 0.2 m;
4) A \u003d 2 N 0.2 m \u003d 0.4 J
Output: In progress
experimental task work
turned out to be 0.4 J.
19. Determination of the work of the elastic force when lifting a load using a fixed block
Use kit #8Using a tripod with a clutch, the block
fixed, thread, 3 weights,
school dynamometer, ruler,
determine the work done by the force
elasticity when lifting three
loads to a height of 20 cm.
On the answer sheet:
1) make a drawing
experimental setup;
2) give a formula for
calculating the work of a force
elasticity;
3) indicate the results of direct
height and strength measurements
elasticity;
4) Calculate the work of the force
elasticity when lifting three
cargo to the specified height;
Example of a possible solution
1) Scheme of the experimental setup
2) A = Fcontrol.h;
3) F ex. = 3.2 N
(with uniform movement); h = 0.2 m;
4) A \u003d 3.2 N 0.2 m \u003d 0.64 J
Output: In progress
experimental task work
elastic force when lifting a body
turned out to be 0.64 J.
20. Determining the work of the current
Use kit #5Using a current source, a voltmeter,
ammeter, key, rheostat,
connecting wires, resistor,
marked R, assemble
experimental setup for
determining the work of electric current
on the resistor. With a rheostat
set the current in the circuit to 0.3 A.
Determine the work of electric current
in 10 minutes.
On the answer sheet:
1) draw the electrical circuit
experiment;
2) write down the formula for calculation
work of electric current;
3) indicate
results
measurements
voltage at a current of 0.3 A;
4) write down
numerical
meaning
work of electric current.
Example of a possible solution
1) Scheme of the experimental setup
Output: In progress
experimental task current work
turned out to be equal to 648 J.
21. Determination of the optical power of a converging lens
Use kit #6Using
gathering
lens,
screen,
ruler,
collect
experimental setup for
definitions
optical
strength
lenses. As a light source
use light from a distant window.
On the answer sheet:
1) make a drawing
experimental setup;
2) write down the formula for calculation
optical power of the lens;
3) indicate the measurement result
focal length of the lens;
4) write down the value of the optical
lens strength.
Example of a possible solution
1) Scheme of the experimental
installations
Output: In progress
experimental task optical
the power of the lens turned out to be 17 diopters.
22. Experimental tasks of the 2nd type
The purpose of the task: to test the ability to representexperimental results in the form of tables or
charts
and
make
findings
on the
basis
obtained experimental data.
Suggested work:
1. dependence of the elastic force arising in the spring,
on the degree of deformation of the spring,
2. dependence of the period of oscillation of the mathematical
pendulum on the length of the thread,
3. dependence of the current strength arising in the conductor, from
voltage at the ends of the conductor,
4. dependence of the sliding friction force on the force
normal pressure,
5. properties of the image obtained using
converging lens.
23. Determination of the dependence of the elastic force arising in the spring on the degree of deformation of the spring
Example of a possible solutionUse kit #3
1) Scheme of the experimental setup
To complete this task, use
laboratory equipment: tripod with clutch and
foot, spring, dynamometer, ruler and set
from three loads. Set Force Dependency
spring tension. Determine
stretching the spring by suspending it
alternately one, two and three weights. For
to determine the weight of goods, use
dynamometer.
On the answer sheet:
1) make the drawing experimental
installations;
2) Write down the weight measurement results
loads, spring extensions;
3) formulate a conclusion about the dependence of the force
elasticity in the spring
spring tension.
experience number
The weight
cargo,
H
Force
elasticity,
H
Elongation,
m
1
1
1
0,025
2
2
2
0,050
3
3
3
0,075
Output: In progress
that the force of elasticity is right
proportional to the stretch of the spring.
24. Determination of the dependence of the period of oscillation of a mathematical pendulum on the length of the thread
Use kit #7To complete this task, use
laboratory equipment: tripod with clutch
and paw; meter ruler (error 5
mm); a ball with a thread attached to it;
clock with a second hand (or stopwatch).
Assemble the experimental setup for
studies of the dependence of the period of free
oscillations of the thread pendulum on the length of the thread.
On the answer sheet:
1)make the drawing experimental
installations;
2) indicate the results of direct measurements of the number
oscillations and oscillation time for three
the length of the pendulum thread in the form of a table;
3)calculate the oscillation period for all three
cases;
4) formulate a conclusion about the dependence of the period
free oscillations of the thread pendulum from
thread length.
Example of a possible solution
1) Scheme of the experimental setup
Output: In progress
experimental task revealed that
with a decrease in the length of the thread, the period
free vibrations decreases.
25. Determination of the dependence of the force of sliding friction on the force of normal pressure
Example of a possible solution1) Scheme of the experimental setup
Use kit #4
Using a carriage (bar) with
crochet, dynamometer, three weights,
guide rail, assemble
experimental setup for
determining the dependence of force
sliding friction from force
normal pressure
On the answer sheet:
1) draw the scheme of the experiment
2) indicate the measurement results
3) formulate a conclusion about
friction force dependences
sliding from the force
normal pressure
Ftr \u003d Fdraught - with uniform movement,
Loading the bar with one, two, three loads,
in each case, we measure the friction force and the force
pressure (gravity), measurement results
write in a table
experience number
The power of normal
pressure, N
Friction force, N
1
2
0,4
2
3
0,8
3
4
1,2
Conclusion: During the execution of the experimental
task, it turned out that the friction force of the spring is directly
proportional to the force of normal pressure.
26. Determining the properties of an image obtained with a converging lens
Determining the properties of an image obtained usingconverging lens
Use kit #6
Using a converging lens,
screen, ruler, working field,
DC power supply
4.5 V, connecting wires,
assemble a key, a lamp on a stand
experimental setup for
defining image properties,
obtained through
converging lens
On the answer sheet:
1) do
picture
experimental setup;
2) indicate the measurement result
focal length of the lens;
3) conclude how they change
properties
images,
received
with
help
gathering
lenses
at
moving the object away from the lens.
Example of a possible solution
1) Scheme of the experimental
installations
d
d
imaginary, enlarged,
direct
F< d < 2F
Real,
enlarged, inverted
d > 2F
Real,
reduced, inverted
Conclusion: When an object is removed from the lens
image of an object from the imaginary
becomes real, and
sizes are reduced.
27. Determination of the dependence of the current strength that occurs in the conductor on the voltage at the ends of the conductor
Use kit #5Using a current source (4.5V),
voltmeter, ammeter, key, rheostat,
connecting wires, resistor,
labeled R2, assemble
experimental setup for
studies of the dependence of the current strength,
arising in the conductor, from
voltage at the ends of the conductor.
On the answer sheet:
1) draw the electrical circuit
experiment;
2) specify
results
measurements
voltage at current
at
different
provisions
slider
rheostat;
3) Make a conclusion about the dependence of force
current arising in the conductor, from
voltage at the ends of the conductor
Example of a possible solution
1) Scheme of the experimental
installations
experience number
I, A
U, B
1
0,2
2,4
2
0,3
3,6
3
0,4
4,8
Conclusion:
AT
progress
fulfillment
experimental task, it turned out that
with increasing voltage between the ends
conductor current strength in the conductor also
increases.
28. Experimental tasks of the 3rd type
Targetworks:
examination
experimental
skills
verification
conduct
physical
laws and consequences.
Suggested verification activities:
1. The law of serial connection
resistors for electrical voltage
2. The law of parallel connection of resistors
for electric current
29. Checking the laws of series connection of resistors for electrical voltage
Use kit #5Using a current source (4.5 V), a voltmeter,
ammeter, key, rheostat, connecting
wires, resistors marked R1 and R2
assemble the experimental setup for
test rule for electrical
voltage in series
connecting resistors.
On the answer sheet:
experiment;
2. Measure the voltage across each
including both resistors;
3. Compare the voltage across each
resistor and the total voltage in the section,
including both resistors
Example of a possible solution
1) Scheme of the experimental
installations
U, V
U1, V
U2, V
Conclusion
3
2
1
U=U1+U2
Conclusion: The total voltage on two
resistors connected in series
equal to the sum of the voltages on each
resistors.
30. Checking the laws of parallel connection of resistors for current strength
Use kit #5Using a current source (4.5V),
voltmeter, ammeter, key, rheostat,
connecting wires, resistors,
labeled R1 and R2 assemble
experimental setup for
checking the rule for current strength at
parallel connection of resistors.
On the answer sheet:
1. draw the wiring diagram
experiment;
2. measure the current in each branch
chains and in an unbranched area;
3. compare the current strength on the main
conductor with the sum of the currents in
conductors connected in parallel
4. draw a conclusion about fairness or
the error of the rule under test.
Example of a possible solution
1) Scheme of the experimental setup
I, A
I1,A
I2 , A
Conclusion
0,6
0,4
0,2
I=I1+I2
Output: In progress
experimental task turned out to be
what is the current strength on the main conductor
equal to the sum of the currents in parallel
connected conductors.
31. Literature
1.2.
3.
4.
Specification of control measuring materials for
holding in 2016 the main state exam in
PHYSICS
Physics Grade 7, A.V. Peryshkin, Drofa LLC, 2014
Physics Grade 8, A.V. Peryshkin, Drofa LLC, 2014
Physics Grade 9, A.V. Peryshkin, Drofa LLC, 2012
Description of the presentation on individual slides:
1 slide
Description of the slide:
Guidelines for the implementation of the experimental tasks of the OGE-2016 in physics Materials prepared by Mytsko Tamara Semyonovna, teacher of physics, MOU-SOSH, village of Kalininskoye, Marksovsky district, Saratov region, 2015.
2 slide
Description of the slide:
The structure of the KIM variant provides verification of all types of activities provided for by the Federal Component of the State Educational Standard: mastering the conceptual apparatus of the basic school physics course, mastering methodological knowledge and experimental skills, using texts of physical content when performing educational tasks, applying knowledge in solving computational problems and explaining physical phenomena and processes in situations of a practice-oriented nature. Possession of the basic knowledge about the methods of scientific knowledge and experimental skills are tested in tasks 18, 19 and 23. Tasks 18 and 19 control the following skills: - to formulate (distinguish) the goals of conducting (hypothesis, conclusions) of the described experiment or observation; - design an experimental setup, choose the order of the experiment in accordance with the proposed hypothesis; - use physical instruments and measuring instruments for direct measurements of physical quantities; - to analyze the results of experimental studies, including those expressed in the form of a table or graph.
3 slide
Description of the slide:
Experimental tasks No. 23 Experimental skills are tested by tasks of three types: tasks for indirect measurements of physical quantities; tasks that test the ability to present experimental results in the form of tables or graphs and draw conclusions based on the experimental data obtained; tasks that test the ability to conduct an experimental verification of physical laws;
4 slide
Description of the slide:
Criteria for assessing the performance of task No. 23 Completely correct performance of the task is assessed by 4 points, for this you need: a schematic drawing of the experimental setup; a formula for calculating the desired value according to the values \u200b\u200bavailable for measurement; correctly recorded results of direct measurements (physical quantities are indicated, direct measurements of which must be carried out in this task); the resulting correct numerical value of the desired value.
5 slide
Description of the slide:
List of equipment sets The list of equipment sets for carrying out experimental tasks is compiled on the basis of typical sets for frontal work in physics. Set No. 1 lever scales with a set of weights measuring cylinder (beaker) with a measurement limit of 100 ml, C = 1 ml glass of water steel cylinder on a thread V = 20 cm3, m = 156 g, designate No. 1 brass cylinder on a thread V = 20 cm3, m = 170 g, designate No. 2 Set No. 2 dynamometer with a measurement limit of 4 N (C = 0.1 N) a glass of water steel cylinder on a thread V = 20 cm3, m = 156 g, designate No. 1 brass cylinder on threads V = 20 cm3, m = 170 g, designate No. 2
6 slide
Description of the slide:
Set No. 4 carriage with a hook on a thread m = 100 g three weights weighing (100 ± 2) g school dynamometer with a measurement limit of 4 N (C = 0.1 N) guide (coefficient of friction of the carriage along the guide is approximately 0.2) Set No. 3 laboratory tripod with clutch and foot spring stiffness (40 ± 1) N/m three weights weighing (100 ± 2) g each school dynamometer with a measurement limit of 4 N (C = 0.1 N) a ruler 200–300 mm long with in millimeter divisions Set No. 5 DC power supply 4.5 V voltmeter 0-6 V, C \u003d 0.2 V ammeter 0-2 A, C \u003d 0.1 A variable resistor (rheostat), 10 Ohm resistor, R1 \u003d 12 ohm, designate R1 resistor, R2 = 6 ohm, designate R2 connecting wires, 8 pcs. key working field Set No. 6 converging lens, focal length F1 = 60 mm, designate L1 ruler 200–300 mm long with millimeter divisions screen working field DC power supply 4.5 V connecting wires key lamp on a stand
7 slide
Description of the slide:
Set No. 7 tripod with clutch and foot meter ruler (error 5 mm) ball with a thread 110 cm long attached to it clock with a second hand (or stopwatch) Set No. 8 tripod with clutch lever block movable block fixed thread three loads weighing (100 ±2) g school dynamometer with a measurement limit of 4 N (C = 0.1 N) a ruler 200-300 mm long with millimeter divisions
8 slide
Description of the slide:
Experimental tasks of the 1st type The purpose of the task: to test the ability to make indirect measurements of physical quantities. Suggested works: density of matter, Archimedes force, coefficient of sliding friction, spring stiffness, period and frequency of oscillation of a mathematical pendulum, moment of force acting on the lever, work of the elastic force when lifting a load using a movable or fixed block, work of the friction force, optical force collecting lens, electrical resistance of the resistor, the work of the electric current, the power of the electric current.
9 slide
Description of the slide:
Determination of the density of a substance Use kit No. 1 Using a balance with a weight, a beaker, a glass of water, cylinder No. 2, assemble an experimental setup for measuring the density of the material from which cylinder No. 2 is made. In the answer sheet: make a drawing of an experimental setup for determining the volume of a body ; write down the formula for calculating density; indicate the results of measuring the mass of the cylinder and its volume; write down the numerical value of the material density of the cylinder. Example of a possible solution 1) Scheme of the experimental setup Conclusion: During the execution of the experimental task, the density of the substance from which the cylinder was made turned out to be 8500 kg/m3.
10 slide
Description of the slide:
Determining the Archimedes Force Use kit #2 Using a dynamometer, a glass of water, cylinder #1, assemble an experimental setup to determine the buoyancy force (Archimedes force) acting on the cylinder. In the answer sheet: make a drawing of the experimental setup; write down the formula for calculating the buoyancy force; indicate the results of measurements of the weight of the cylinder in air and the weight of the cylinder in water; write down the numerical value of the buoyant force. Example of a possible solution 1) Scheme of the experimental setup Conclusion: During the execution of the experimental task, the Archimedes force turned out to be 0.2 N.
11 slide
Description of the slide:
Determination of the coefficient of sliding friction Use kit No. 4 Using a carriage (bar) with a hook, a dynamometer, one weight, a guide rail, assemble an experimental setup for measuring the coefficient of sliding friction between the carriage and the surface of the rail. In the answer sheet: make a drawing of the experimental setup; write down the formula for calculating the coefficient of sliding friction; indicate the results of measurements of the weight of the carriage with the load and the force of sliding friction when the carriage with the load moves along the surface of the rail; write down the numerical value of the coefficient of sliding friction. Conclusion: In the course of the experimental task, the coefficient of sliding friction turned out to be 0.2. Example of a possible solution 1) Schematic of the experimental setup
12 slide
Description of the slide:
Determination of the moment of force acting on the lever Use kit #8 Using the lever, three weights, a tripod and a dynamometer, assemble the installation for studying the balance of the lever. Hang three weights to the left of the axis of rotation of the lever as follows: two weights at a distance of 6 cm and one weight at a distance of 12 cm from the axis. Determine the moment of force that must be applied to the right end of the lever at a distance of 12 cm from the axis of rotation of the lever in order for it to remain in balance in a horizontal position. In the answer sheet: draw a diagram of the experimental setup; write down the formula for calculating the moment of force; indicate the results of measurements of the applied force and arm length; write down the numerical value of the moment of force. 2) M=Fl 3) F = 2N, l = 0.12 m 4) M = 2N 0.12 m = 0.3 N m Conclusion: During the experimental task, the moment of force that must be applied to the right end lever turned out to be 0.3 N m. An example of a possible solution 1) Scheme of the experimental setup
13 slide
Description of the slide:
Determining the Spring Stiffness Use Kit #3 Using a tripod with clutch and foot, spring, dynamometer, ruler and two weights, assemble an experimental setup to measure the spring constant. Determine the stiffness of the spring by hanging two weights from it. Use a dynamometer to measure the weight of loads. In the answer sheet: Make a drawing of the experimental setup; write down the formula for calculating the stiffness of the spring; indicate the results of measuring the weight of the loads and the elongation of the spring; write down the numerical value of the spring constant. Conclusion: In the course of the experimental task, the stiffness coefficient turned out to be 40 N/m. Example of a possible solution 1) Schematic of the experimental setup
14 slide
Description of the slide:
Determination of the period and frequency of oscillations of a mathematical pendulum meter ruler (error 5 mm); a ball with a thread attached to it; clock with a second hand (or stopwatch). Assemble an experimental setup to determine the period and frequency of free oscillations of a thread pendulum. In the answer sheet: make a drawing of the experimental setup; Give a formula for calculating the period and frequency of oscillations; indicate the results of direct measurements of the number of oscillations and the time of oscillations for the length of the pendulum thread equal to 0.5 m; calculate the period and frequency of oscillation; Conclusion: During the execution of the experimental task, the period of free oscillations turned out to be 1.4 s, the frequency was 0.7 Hz. 3) N = 30; t = 42 s. 4) T \u003d t / N \u003d 1.4 s; ν \u003d 1 / T \u003d 0.7 Hz. 2) T = t/N; v = 1/T; Example of a possible solution 1) Schematic of the experimental setup
15 slide
Description of the slide:
Determination of the work of the friction force Use kit No. 4 Using a carriage (bar) with a hook, a dynamometer, one weight, a guide rail, assemble an experimental setup to determine the work of the friction force when the carriage with the load moves in the horizontal direction for the length of the rail. In the answer sheet: make a drawing of the experimental setup; write down the formula for calculating the work of the friction force; indicate the results of measurements of the sliding friction force when the carriage with the load moves along the surface of the rail, the length of the rail; write down the numeric value. the work of the friction force. A sample of a possible solution 1) Scheme of the experimental setup Conclusion: During the execution of the experimental task, the work of sliding friction turned out to be equal to 2 J 2) A=Ftr · s; Ftr = Fthrust (with uniform motion); 4) A= 0.4 N 0.5 m=2 J. 3) Fthrust = 0.4 N; l = 0.5 m;
16 slide
Description of the slide:
Determining the electrical resistance of the resistor Use kit #5 Determine the electrical resistance of the resistor R1. To do this, assemble an experimental setup using a 4.5 V current source, a voltmeter, an ammeter, a key, a rheostat, connecting wires and a resistor marked R1. Using a rheostat, set the current in the circuit to 0.2 A. In the answer sheet: draw an electrical circuit of the experiment; write down the formula for calculating electrical resistance; indicate the results of voltage measurement at a current strength of 0.2 A; write down the numerical value of the electrical resistance. Conclusion: During the execution of the experimental task, the resistance of the resistor R1 turned out to be 12 ohms. Example of a possible solution 1) Schematic of the experimental setup
17 slide
Description of the slide:
Determination of current power Use kit #5 Using a current source (4.5 V), a voltmeter, an ammeter, a key, a rheostat, connecting wires, a resistor marked R2, assemble an experimental setup to determine the power dissipated in a resistor at a current of 0.5 A In the answer sheet: draw the electrical circuit of the experiment; write down the formula for calculating the power of electric current; indicate the results of voltage measurement at a current strength of 0.5 A; write down the numerical value of the power of the electric current. Conclusion: During the execution of the experimental task, the power of the electric current turned out to be 1.5 watts. Example of a possible solution 1) Schematic of the experimental setup
18 slide
Description of the slide:
Determination of the work of the elastic force when lifting a load using a movable block Use kit No. 8 Using a tripod with a clutch, a movable block, a thread, 3 weights, a school dynamometer, a ruler, determine the work of the elastic force when lifting three loads to a height of 20 cm. In the answer sheet: draw a drawing of the experimental setup; give a formula for calculating the work of the elastic force; indicate the results of direct measurements of height and elastic force; Calculate the work of the elastic force when lifting three loads to the specified height; 2) A = Fcontrol.h; 3) F ex. \u003d 2 N (with uniform movement); h = 0.2 m; 4) A = 2 N 0.2 m = 0.4 J Conclusion: During the execution of the experimental task, the work of the elastic force when lifting the body turned out to be 0.4 J. An example of a possible solution 1) Scheme of the experimental setup
19 slide
Description of the slide:
Determination of the work of the elastic force when lifting a load using a fixed block Use kit No. 8 Using a tripod with a clutch, a fixed block, a thread, 3 weights, a school dynamometer, a ruler, determine the work of the elastic force when lifting three loads to a height of 20 cm. In the answer sheet: draw a drawing of the experimental setup; give a formula for calculating the work of the elastic force; indicate the results of direct measurements of height and elastic force; Calculate the work of the elastic force when lifting three loads to the specified height; 2) A = Fcontrol.h; 3) F ex. = 3.2 N (with uniform movement); h = 0.2 m; 4) A = 3.2 N 0.2 m = 0.64 J Conclusion: During the execution of the experimental task, the work of the elastic force when lifting the body turned out to be 0.64 J. An example of a possible solution 1) Scheme of the experimental setup
20 slide
Description of the slide:
Determination of Current Work Use kit #5 Using a current source, voltmeter, ammeter, key, rheostat, connecting wires, resistor marked R, assemble an experimental setup to determine the work of electric current on a resistor. Using a rheostat, set the current in the circuit to 0.3 A. Determine the work of the electric current in 10 minutes. In the answer sheet: draw an electrical circuit of the experiment; write down the formula for calculating the work of an electric current; indicate the results of voltage measurement at a current strength of 0.3 A; write down the numerical value of the work of the electric current. Conclusion: During the execution of the experimental task, the work of the current turned out to be 648 J. An example of a possible solution 1) Scheme of the experimental setup
21 slide
Description of the slide:
Determination of the optical power of a converging lens Use kit No. 6 Using a converging lens, a screen, a ruler, assemble an experimental setup for determining the optical power of a lens. Use light from a distant window as the light source. In the answer sheet: make a drawing of the experimental setup; write down the formula for calculating the optical power of a lens; indicate the result of measuring the focal length of the lens; write down the value of the optical power of the lens. Conclusion: In the course of the experimental task, the optical power of the lens turned out to be 17 diopters. Example of a possible solution 1) Schematic of the experimental setup
22 slide
Description of the slide:
Experimental tasks of the 2nd type The purpose of the task: to test the ability to present experimental results in the form of tables or graphs and draw conclusions based on the experimental data obtained. Suggested works: dependence of the elastic force arising in the spring on the degree of deformation of the spring, dependence of the period of oscillation of a mathematical pendulum on the length of the thread, dependence of the current strength arising in the conductor on the voltage at the ends of the conductor, dependence of the sliding friction force on the force of normal pressure, image properties obtained with a converging lens.
23 slide
Description of the slide:
Determining the dependence of the elastic force arising in the spring on the degree of deformation of the spring Use kit No. 3 To complete this task, use laboratory equipment: a tripod with a clutch and foot, a spring, a dynamometer, a ruler and a set of three weights. Establish the dependence of the elastic force arising in the spring on the magnitude of the stretching of the spring. Determine the tension of the spring by hanging one, two and three weights alternately from it. Use a dynamometer to determine the weight of the loads. In the answer sheet: make a drawing of the experimental setup; write down the results of measuring the weight of the goods, the elongation of the spring; formulate a conclusion about the dependence of the elastic force arising in the spring on the magnitude of the stretching of the spring. Conclusion: In the course of the experimental task, it turned out that the elastic force is directly proportional to the stretching of the spring. Example of a possible solution 1) Scheme of the experimental setup Experiment No. Load weight, N Elastic force, N Elongation, m 1 1 1 0.025 2 2 2 0.050 3 3 3 0.075
24 slide
Description of the slide:
Determining the dependence of the period of oscillation of a mathematical pendulum on the length of the thread Use kit No. 7 To complete this task, use laboratory equipment: a tripod with a clutch and foot; meter ruler (error 5 mm); a ball with a thread attached to it; clock with a second hand (or stopwatch). Assemble an experimental setup to study the dependence of the period of free oscillations of a filament pendulum on the length of the filament. In the answer sheet: make a drawing of the experimental setup; indicate the results of direct measurements of the number of oscillations and the oscillation time for three lengths of the pendulum thread in the form of a table; calculate the oscillation period for all three cases; formulate a conclusion about the dependence of the period of free oscillations of a thread pendulum on the length of the thread. Conclusion: During the execution of the experimental task, it turned out that with a decrease in the length of the thread, the period of free oscillations decreases. Example of a possible solution 1) Schematic of the experimental setup
25 slide
Description of the slide:
Determining the dependence of the sliding friction force on the normal pressure force Use kit No. 4 Using a carriage (bar) with a hook, a dynamometer, three weights, a guide rail, assemble an experimental setup to determine the dependence of the sliding friction force on the normal pressure force In the answer sheet: draw a diagram of the experiment, indicate measurement results formulate a conclusion about the dependence of the sliding friction force on the force of normal pressure Conclusion: In the course of the experimental task, it turned out that the friction force of the spring is directly proportional to the force of normal pressure. A sample of a possible solution 1) Scheme of the experimental setup Ftr = Fdraught - with uniform motion, Loading the bar with one, two, three loads, we measure the friction force and pressure force (gravity) in each case, we record the measurement results in the table Experiment No. Force of normal pressure, N Friction force, N 1 2 0.4 2 3 0.8 3 4 1.2
26 slide
Description of the slide:
Determination of the properties of an image obtained with a converging lens Use kit No. 6 using a converging lens In the answer sheet: make a drawing of the experimental setup; indicate the result of measuring the focal length of the lens; draw a conclusion about how the properties of images obtained with a converging lens change when the object is removed from the lens. Conclusion: When an object is removed from the lens, the image of the object from the imaginary becomes real, and its size decreases. Example of a possible solution 1) Schematic of the experimental setup d Image properties d< F Мнимое, увеличенное, прямое F< d< 2F Действительное, увеличенное, перевернутое d >2F Real, diminished, inverted
27 slide
Description of the slide:
Determination of the dependence of the current strength arising in the conductor on the voltage at the ends of the conductor the strength of the current arising in the conductor, from the voltage at the ends of the conductor. In the answer sheet: draw an electrical circuit of the experiment; indicate the results of measuring voltage at current strength at different positions of the rheostat slider; Draw a conclusion about the dependence of the current strength that occurs in the conductor on the voltage at the ends of the conductor Conclusion: In the course of the experimental task, it turned out that with an increase in the voltage between the ends of the conductor, the current strength in the conductor also increases. Sample possible solution 1) Scheme of the experimental setup Experiment No. I,A U,B 1 0.2 2.4 2 0.3 3.6 3 0.4 4.8
Description of the slide:
Checking the laws of series connection of resistors for electrical voltage Use kit #5 Using a current source (4.5 V), a voltmeter, an ammeter, a key, a rheostat, connecting wires, resistors marked R1 and R2, assemble an experimental setup to test the rule for electrical voltage in series connecting resistors. In the answer sheet: 1. draw the electrical circuit of the experiment; 2. measure the voltage across each resistor and the total voltage across the section that includes both resistors; 3. Compare the voltage across each resistor and the total voltage across the section that includes both resistors 4. Make a conclusion about the validity or fallacy of the tested rule. Conclusion: The total voltage across two resistors connected in series is equal to the sum of the voltages across each of the resistors. Sample possible solution 1) Scheme of the experimental setup U, V U1, V U2, V Conclusion 3 2 1 U=U1+U2
30 slide
Description of the slide:
Checking the laws of parallel connection of resistors for current Use kit #5 Using a current source (4.5 V), a voltmeter, an ammeter, a key, a rheostat, connecting wires, resistors marked R1 and R2, assemble an experimental setup to test the rule for current in parallel connecting resistors. In the answer sheet: 1. draw the electrical circuit of the experiment; 2. measure the current in each branch of the circuit and in the unbranched section; 3. compare the strength of the current on the main conductor with the sum of the strengths of the currents in parallel-connected conductors, 4. draw a conclusion about the validity or fallacy of the rule being tested. Conclusion: In the course of the experimental task, it turned out that the current strength on the main conductor is equal to the sum of the current strengths in parallel-connected conductors. Sample possible solution 1) Pilot setup I,A I1,A I2,A Conclusion 0.6 0.4 0.2 I=I1+I2
31 slide
Description of the slide:
Literature Specification of control measuring materials for the main state exam in PHYSICS in 2016 Physics Grade 7, A.V. Peryshkin, Drofa LLC, 2014 Physics grade 8, A.V. Peryshkin, Drofa LLC, 2014 Physics Grade 9, A.V. Peryshkin, Drofa LLC, 2012
PRACTICAL WORKS ON OGE PHYSICS 9 CLASS.
1. Determination of the frequency of free oscillations of a thread pendulum
Using a tripod with a clutch and foot, a weight with a thread attached to it, a meter ruler and a stopwatch, assemble an experimental setup for studying the free oscillations of a thread pendulum. Determine the time of 30 complete oscillations and calculate the oscillation frequency for the case when the length of the thread is 1 m.
On the answer sheet:
2) write down the formula for calculating the oscillation frequency;
4) write down the numerical value of the oscillation frequency of the pendulum.
2. Dependence of the elastic force on the degree of stretching of the spring
Using a tripod with a clutch and foot, a spring, a dynamometer, a ruler and a set of three weights, assemble an experimental setup to study the dependence of the elastic force that occurs in the spring on the degree of stretching of the spring. Determine the tension of the spring by hanging one, two and three weights alternately from it. Use a dynamometer to determine the weight of the loads.
On the answer sheet:
1) draw a drawing of the experimental setup;
2) indicate the results of measuring the weight of the goods and the elongation of the spring for three cases in the form of a table (or graph);
3) formulate a conclusion about the dependence of the elastic force arising in the spring on the degree of stretching of the spring.
Example of a possible implementation
3.. Determining the stiffness of the spring
To complete this task, use laboratory equipment: a tripod with a clutch and foot, a spring, a dynamometer, a ruler, and two weights. Assemble an experimental setup to determine the stiffness of the spring. Determine the stiffness of the spring by hanging two weights from it. Use a dynamometer to determine the weight of the loads.
When completing a task:
1) draw a drawing of the experimental setup;
2) write down the formula for calculating the stiffness of the spring;
3) indicate the results of measuring the weight of the weights and the elongation of the spring;
4) write down the numerical value of the spring stiffness.
Example of a possible implementation
4. Dependence of the period of free oscillations of a thread pendulum on the length
Using a tripod with a clutch and foot, a ball with a thread attached to it, a ruler and a clock with a second hand (or a stopwatch), assemble an experimental setup to study the dependence of the period of free oscillations of a thread pendulum on the length of the thread. Determine the time for 30 complete oscillations and calculate the period of oscillation for three cases when the length of the thread is 1 m, 0.5 m and 0.25 m, respectively.
On the answer sheet:
1) draw a drawing of the experimental setup;
2) indicate the results of direct measurements of the number of oscillations and the oscillation time for three lengths of the pendulum thread in the form of a table;
3) calculate the oscillation period for each case and enter the results in the table;
4) formulate a qualitative conclusion about the dependence of the period of free oscillations of the thread pendulum on the length of the thread.
Example of a possible implementation
5. Measuring the coefficient of sliding friction
Using a carriage (bar) with a hook, a dynamometer, one weight, a guide rail, assemble an experimental setup to measure the coefficient of sliding friction between the carriage and the surface of the rail.
On the answer sheet:
1) draw a drawing of the experimental setup;
2) write down the formula for calculating the coefficient of sliding friction;
3) indicate the results of measuring the weight of the carriage with the load and the sliding friction force when the carriage with the load moves along the surface of the rail;
4) write down the numerical value of the coefficient of sliding friction.
Example of a possible implementation
6. Dependence of the period of free oscillations of a spring pendulum on the mass of the load
Using a tripod with a clutch and foot, a spring, a set of weights and a stopwatch, assemble an experimental setup for studying the free oscillations of a spring pendulum. Determine the time for 20-30 complete oscillations and calculate the oscillation period for loads of various masses.
On the answer sheet:
1) draw a drawing of the experimental setup;
2) measure the duration of 20-30 complete oscillations for loads of three different masses, present the results in a table;
3) calculate the oscillation period for each case, round the results to hundredths of a second and enter in the table;
4) formulate a conclusion about the dependence of the period of free oscillations of a spring pendulum on the mass of the load.
Example of a possible implementation
7. Determination of the moment of force applied to the lever
Using a lever, three weights, a tripod and a dynamometer, assemble the setup for studying the balance of the lever. Hang three weights to the left of the axis of rotation of the lever as follows: two weights at a distance of 6 cm and one weight at a distance of 12 cm from the axis. Determine the moment of force that must be applied to the right end of the lever at a distance of 6 cm from the axis of rotation of the lever in order for it to remain in balance in a horizontal position.
On the answer sheet:
1) draw a diagram of the experimental setup;
2) write down the formula for calculating the moment of force;
3) indicate the results of measurements of the applied force and arm length;
4) write down the numerical value of the moment of force.
Example of a possible implementation
8. Density determination
Using a weight balance, a beaker, a glass of water, a cylinder, assemble an experimental setup to measure the density of the material from which the cylinder is made.
On the answer sheet:
1) draw a drawing of an experimental setup for determining the volume of a body;
2) write down the formula for calculating the density;
3) indicate the results of measuring the mass of the cylinder and its volume;
4) write down the numerical value of the material density of the cylinder.
Example of a possible implementation
9. Buoyancy measurement
Assemble the experimental setup for measuring the buoyancy force.
On the answer sheet:
2) write down the formula for calculating the buoyancy force;
4) write down the numerical value of the buoyancy force.
Example of a possible implementation
10. Friction force work
Using a carriage (bar) with a hook, a dynamometer, two weights, a guide rail, assemble an experimental setup for measuring the work of the sliding friction force when the carriage with weights moves along the surface of the rail for a distance of 40 cm.
On the answer sheet:
1) draw a drawing of the experimental setup;
2) write down the formula for calculating the work of the sliding friction force;
3) indicate the results of measuring the displacement module of the carriage with loads and the sliding friction force when the carriage with loads moves along the surface of the rail;
4) write down the numerical value of the sliding friction work.
Example of a possible implementation
11. Study of the dependence of the sliding friction force on the normal pressure force
Using a carriage (bar) with a hook, a dynamometer, two weights, a guide rail, assemble an experimental setup to study the dependence of the sliding friction force on the normal pressure force.
On the answer sheet:
1) draw the scheme of the experiment;
2) write down the formula for calculating the force of sliding friction;
3) indicate the measurement results;
4) formulate a conclusion about the dependence of the sliding friction force on the force of normal pressure.
Example of a possible implementation
12. Measurement of the period of free oscillations of a thread pendulum
Using a tripod with a clutch and foot, a weight with a thread attached to it, a meter ruler and a stopwatch, assemble an experimental setup for studying the period of free oscillations of a thread pendulum. Determine the time for 30 complete oscillations and calculate the oscillation period for the case when the length of the thread is 1 m.
On the answer sheet:
1) draw a drawing of the experimental setup;
2) write down the formula for calculating the oscillation period;
3) indicate the results of direct measurements of the number of oscillations and the time of oscillations;
4) write down the numerical value of the period of oscillation of the pendulum.
Example of a possible implementation
13. Determination of the work of the elastic force when lifting a load using a fixed block
Using a tripod with a clutch, a fixed block, a thread, three weights and a dynamometer, assemble an experimental setup for measuring the work of the elastic force when lifting loads uniformly using a fixed block. Calculate the work done by the elastic force when lifting the load to a height of 20 cm.
On the answer sheet:
1) draw a drawing of the experimental setup;
2) write down the formula for calculating the work of the elastic force;
3) indicate the results of direct measurements of the elastic force and path;
4) write down the numerical value of the work of the elastic force.
Example of a possible implementation
14. Determination of the optical power of the lens
Using a converging lens, a screen, a ruler, assemble an experimental setup to determine the optical power of the lens. Use light from a distant window as the light source.
On the answer sheet:
1) draw a drawing of the experimental setup;
2) write down the formula for calculating the optical power of the lens;
3) indicate the result of measuring the focal length of the lens;
4) write down the numerical value of the optical power of the lens.
Example of a possible implementation
15. Voltage when two conductors are connected in series
Using a current source (4.5 V), voltmeter, key, connecting wires, resistors marked R 1 and R 2 , check experimentally the rule for electric voltage when two conductors are connected in series.
On the answer sheet:
2) measure the voltage at the ends of each of the resistors and the total voltage at the ends of the circuit of two resistors when they are connected in series;
3) compare the total voltage across the two resistors with the sum of the voltages across each of the resistors, considering that the error of direct measurements with a laboratory voltmeter is 0.2 V.
Make a conclusion about the validity or fallacy of the rule being tested.
Example of a possible implementation
16. Dependence of the voltage at the ends of the conductor on the strength of the electric current
Using a current source (4.5 V), voltmeter, ammeter, key, rheostat, connecting wires, resistor marked R 1 , assemble an experimental setup to study the dependence of the electric current in the resistor on the voltage at its ends.
On the answer sheet:
Example of a possible implementation
17. Determination of the electrical resistance of a resistor
For this task, use laboratory equipment: current source (4.5 V), voltmeter, ammeter, key, rheostat, connecting wires, resistor marked R 1 . Assemble an experimental setup to determine the electrical resistance of a resistor. Using a rheostat, set the current in the circuit to 0.5 A.
On the answer sheet:
1) draw the electrical circuit of the experiment;
2) write down the formula for calculating electrical resistance;
4) write down the numerical value of the electrical resistance.
Example of a possible implementation
18. Study of the dependence of the strength of the electric current in the resistor on the voltage at its ends
Using a current source (4.5 V), a voltmeter, an ammeter, a key, a rheostat, connecting wires, a resistor, assemble an experimental setup to study the dependence of the electric current in the resistor on the voltage at its ends.
On the answer sheet:
1) draw the electrical circuit of the experiment;
2) using a rheostat, setting in turn the current strength in the circuit 0.4 A, 0.5 A and 0.6 A and measuring in each case the values of the electrical voltage at the ends of the resistor, indicate the results of measuring the current strength and voltage for three cases in the form of a table (or graphics);
3) formulate a conclusion about the dependence of the electric current in the resistor on the voltage at its ends.
Example of a possible implementation
19. Determination of the power of electric current
Using a current source (4.5 V), a voltmeter, an ammeter, a key, a rheostat, connecting wires, a resistor, assemble an experimental setup to determine the power dissipated in the resistor. Using a rheostat, set the current in the circuit to 0.5 A.
On the answer sheet:
1) draw the electrical circuit of the experiment;
2) write down the formula for calculating the power of electric current;
3) indicate the results of voltage measurement at a current strength of 0.5 A;
4) write down the numerical value of the power of the electric current.
Example of a possible implementation
20. Current strength with parallel connection of two conductors
Using a current source (4.5 V), an ammeter, a key, connecting wires, resistors marked R1 and R2, check experimentally the rule for electric voltage when two conductors are connected in series.
On the answer sheet:
1) draw the electrical circuit of the experimental setup;
2) measure the current strength on each of the resistors and the total current strength in the circuit when they are connected in parallel;
3) compare the total current in the circuit with the sum of the currents on each of the resistors, given that the error of direct measurements using a laboratory ammeter is 0.05 A. Make a conclusion about the validity or fallacy of the rule being tested.
Example of a possible solution
21. Determination of the work of electric current
To complete this task, use laboratory equipment: a current source (4.5 V), a voltmeter, an ammeter, a key, a rheostat, connecting wires, a resistor R. Assemble an experimental setup for measuring the work of an electric current. Using a rheostat, set the current in the circuit to 0.5 A.
On the answer sheet:
1) draw the electrical circuit of the experiment;
2) write down the formula for calculating the work of an electric current;
3) indicate the results of voltage measurement at a current strength of 0.5 A for 10 minutes;
4) write down the numerical value of the work of the electric current.
Example of a possible implementation
PRACTICAL PART OGE PHYSICS 9