Laboratory work 1 observation. Observation of the effect of a magnetic field on a current. Training tasks and questions

Working process.

Equipment: tripod with clutch and foot, power source, wire coil, arcuate magnet, key, connecting wires.

Work Instructions

1. Assemble the installation shown in Figure 144, b. By bringing a magnet to the wire coil, close the circuit. Pay attention to character magnetic interaction coil and magnet.

2. Bring the magnet to the skein with the other pole. How has the nature of the interaction between the coil and the magnet changed?

3. Repeat the experiments, placing the magnet on the other side of the skein.

4. Position the wire coil between the poles of the magnet as shown in Figure 144, a. After closing the circuit, observe the phenomenon. Draw your own conclusions.

In work No. 4, we will consider the interaction of a solenoid with a magnet. As is known, a magnetic field arises in a solenoid under current, which will interact with permanent magnet. We will carry out a series of four experiments with different arrangements of the coil and magnet. It should be expected that their interaction will also be different (attraction or repulsion).

Approximate work progress:

We observe the following phenomena, which are conveniently represented in the form of figures:

Objective:

Equipment:

Note.

Working process

spool.

Conclusion: _____

Additional task

Laboratory work № 2

Phenomenon study electromagnetic induction

Objective: study the phenomenon of electromagnetic induction, check Lenz's rule.

Equipment: milliammeter, power supply, coils with cores, arcuate or strip magnet, rheostat, key, connecting wires, magnetic needle.

Training tasks and questions

August 28, 1831 M. Faraday _____
What is the phenomenon of electromagnetic induction?
The magnetic flux Ф through a surface with an area S is called _____
What units are used in the SI system?

a) induction magnetic field[B]= _____

b) magnetic flux[F]= _____

5. Lenz's rule allows you to determine _____

6. Write down the formula for the law of electromagnetic induction.

7. What is physical meaning law of electromagnetic induction?

8. Why is the discovery of the phenomenon of electromagnetic induction classified as one of the greatest discoveries in the field of physics?

Working process

Connect the coil to the terminals of the milliammeter.
Do the following:

a) insert the north (N) pole of the magnet into the coil;

b) stop the magnet for a few seconds;

c) remove the magnet from the coil (the modulus of the speed of the magnet is approximately the same).

3. Write down whether an induction current occurred in the coil and what are its features in each case: a) _____ b) _____ c) _____

4. Repeat step 2 with the south (S) pole of the magnet and draw the appropriate conclusions: a) _____ b) _____ c) _____

5. Formulate under what condition an induction current appeared in the coil.

6. Explain the difference in the direction of the induced current in terms of Lenz's rule

7. Draw a diagram of the experience.

8. Draw a circuit consisting of a current source, two coils on a common core, a key, a rheostat and a milliammeter (connect the first coil to the milliammeter, connect the second coil through the rheostat to the current source).

9. Gather electrical circuit according to this scheme.

10. Closing and opening the key, check whether there is an induction current in the first coil.

11. Check the implementation of the Lenz rule.

12. Check if an induction current occurs when the rheostat current changes.

Lab #3

Working process

Place a tripod on the edge of the table, fasten the ring at its upper end with a coupling and hang the ball on the thread to it. The ball should hang at a distance of 2-5 cm from the floor.
Measure the length of the pendulum with a tape: ℓ= _____
Deviate the pendulum from the equilibrium position by 5-8 cm and release it.
Measure the time of 30-50 complete oscillations (eg N=40). t₁ = _____
Repeat the experiment 4 more times (the number of oscillations in all experiments is the same).

t = _____ t = _____ t = _____ t = _____

Calculate the average value of the oscillation time.

t ,

t t__________ .

Calculate the average value of the oscillation period.

________ .

Enter the results of calculations and measurements in the table.

q q __________

Calculate the absolute time measurement errors in each experiment.

∆t₁=|t₁−t |=| |=

∆t₂=|t₂−t |=| |=

∆t₃=|t₃−t |=| |=

∆t₄=|t₄−t |=| |=

∆t₅=|t₅−t |=| |=

Calculate the mean absolute error of time measurements.

∆t = = _______

Calculate the relative measurement error q using the formula:

, where = 0.75 cm

Calculate the absolute measurement error q.

∆q = _____ ∆q = _____

Lab #4

Working process

Connect the light bulb through the switch to the power source. Use a screen with a slit to get a thin beam of light.
Position the plate so that the light beam falls on it at point B at some sharp angle.
Put two points along the light beam falling on the plate and coming out of it.
Turn off the light bulb and remove the plate, outlining its outline.
Draw the incident and refracted rays through point B of the air-glass interface and mark the angles of incidence α and refraction β.
Draw a circle centered at point B and mark the intersection points of the circle with the incident and reflected rays (points A and C, respectively).
Measure the distance from point A to the perpendicular to the interface. α=____
Measure the distance from point C to the perpendicular to the interface. b= _____
Calculate the refractive index of glass using the formula.

Because n= n= _____

Calculate the relative error in the measurement of the refractive index using the formula:

Where ∆α = ∆b = 0.15 cm. ______ = _____

11. Calculate the absolute measurement error n.

∆n = n ε ∆n = ______ ∆n = _____

12. Write the result as n = n ± ∆n. n = _____

13. Enter the results of calculations and measurements in the table.

experience number	α, cm	B cm	n	∆α, cm	∆b, cm	ε	∆n

14. Repeat measurements and calculations at a different angle of incidence.

15. Compare the obtained results of the refractive index of glass with the table.

Additional task

Lab #5

Working process

1 Assemble the electrical circuit by connecting the light bulb to a power source through a switch.

2. Place the light bulb on one end of the table and the screen on the other end. Place a converging lens between them.

3. Turn on the bulb and move the lens along the rod until a sharp, reduced image of the luminous letter of the bulb cap is obtained on the screen.

4. Measure the distance from the screen to the lens in mm. d=

5. Measure the distance from the lens to the image in mm. f

6. With d unchanged, repeat the experiment 2 more times, each time getting a sharp image again. f , f

7. Calculate the average distance from the image to the lens.

f f f = _______

8. Calculate the optical power of the lens D D

9. Calculate the focal length to the lens. F F =

10. Enter the results of calculations and measurements in the table.

11. Measure lens thickness in mm. h=_____

12. Calculate the absolute error in measuring the optical power of the lens using the formula:

∆D = , ∆D = _____

13. Write the result as D = D ± ∆D D = _____

Lab #6

Working process

Turn on the light source.
Looking through the diffraction grating and the slit in the screen at the light source and moving the grating in the holder, set it so that the diffraction spectra are parallel to the screen scale.
Install the screen approximately 50 cm from the grille.
Measure the distance from the grating to the screen. α= _____
Measure the distance from the screen slit to the red first order line to the left and right of the slit.

Left: b = _____ Right: b=_____

To the right of the gap Violet To the left of the gap To the right of the gap

Repeat measurements and calculations for purple.

Observation of the effect of a magnetic field on current

Objective: make sure that a uniform magnetic field has an orienting effect on the current-carrying loop.

Equipment: spool, tripod, source direct current, rheostat, key, connecting wires, arcuate or strip magnet.

Note. Before work, make sure that the rheostat slider is set to maximum resistance.

Training tasks and questions

In 1820, H. Oersted discovered the action electric current on the _____
In 1820, A. Ampere established that two parallel conductors with a current _____
A magnetic field can be created: a) _____ b) _____ c) _____
What is the main characteristic of a magnetic field? What are the units in the SI system?
For the direction of the magnetic induction vector B in the place where the frame with current is located, take _____
What is the feature of magnetic induction lines?
The gimlet rule allows _____
Ampère's force formula is: F= _____
State the left hand rule.
The maximum torque M acting on the loop with current from the side of the magnetic field depends on _____

Working process

Assemble the chain according to the drawing, hanging it on flexible wires

spool.

Position the arcuate magnet under some sharp

angle α (for example, 45 °) to the plane of the coil-coil and, closing the key, observe the movement of the coil-coil.

Repeat the experiment, first changing the poles of the magnet, and then the direction of the electric current.
Draw a coil and a magnet, indicating the direction of the magnetic field, the direction of the electric current and the nature of the movement of the coil.
Explain the behavior of a current-carrying coil in a uniform magnetic field.
Position the arcuate magnet in the plane of the coil (α=0°). Repeat the steps in steps 2-5.
Position the arcuate magnet perpendicular to the plane of the spool (α=90°). Repeat the steps in steps 2-5.

Conclusion: _____

Additional task

By changing the current strength with a rheostat, observe whether the nature of the movement of the coil-coil with current in a magnetic field changes?

Lab #2

1. PURPOSE OF THE WORK. Observation of the action of a magnetic field on a coil with current, on a straight conductor with current.

2. INSTRUMENTS AND ACCESSORIES. Wire coil, tripod, direct current source, key, bar magnet, arcuate magnet, straight conductor.

BRIEF THEORY

Let us list the main properties of the magnetic field, which are to be observed experimentally, and the questions that a student should be aware of when starting this laboratory work.

1. A magnetic field acts on a current-carrying conductor.

2. - magnetic field induction, a vector physical quantity, is a force characteristic of a magnetic field.

3. The magnetic field can be represented graphically using lines of force. The tangent to the field line has a direction coinciding with the direction of the vector.

4. In Figure 1, with the help of lines of force, the magnetic fields of a bar magnet, rings with current, coils with current, and an arcuate magnet are shown. N is the north magnetic pole, S is the south magnetic pole.

5. When the sources of the magnetic field interact, the poles of the same name repel each other, opposite poles are mutually attracted.

6. Force acting on a wire with current in a magnetic field (Ampère's law):

F a = IB l sina, (1)

where I - force current in the conductor;B– magnetic field induction;l – conductor length; a is the angle between the conductor and the vector. Force vector direction F adetermined by the left hand rule.

WORK TASK

Observation of the action of the magnetic field of a strip magnet on a coil with current.

4.1.1. Hang the coil of wire on a tripod, connect the ends of the wire through the key to the current source.

4.1.2. Bring a strip magnet to a hanging skein and, closing the key, observe the movements of the skein.

4.1.3. Sketch the relative position of the skein and the magnet.

4.1.4. Record the results of the observation in table 1.

Table 1.

The action of a magnetic field on a straight current-carrying conductor.

4.2.1. Place a hanging conductor between the poles of the arcuate magnet.

4.2.2. Sketch the relative position of the arcuate magnet and the straight conductor.

4.2.3. Close the key of the electrical circuit and observe the movement of the conductor.

4.2.4. Reverse the polarity of the current source connection (a reverse current will flow through the conductor) and observe the movement of the conductor.

4.2.5. Record the results of the observation in table 2.

Table 2.

CONCLUSION

In the conclusion, analyze the experimental results and answer the following questions.

1. Does a magnetic field act on a conductor with current, on a conductor without current?

2. Do the results of the task confirm 4.1 point 5 from the section " BRIEF THEORY»?

3. Do the results of the task confirm 4.2 point 6 from the section " BRIEF THEORY»?

TEST QUESTIONS

6.1. What does the magnetic field affect?

6.2. What physical quantity is the force characteristic of the magnetic field, how is it used?

6.3. What is a magnetic field line, what are lines of force used for?

6.4. Draw the magnetic field of a bar magnet using lines of force. Specify north and south magnetic poles magnet.

6.5. How do like magnetic poles and unlike magnetic poles interact with each other?

6.6. How are the magnitude and direction of the force acting on a wire carrying current in a magnetic field determined?

1. Prepare a table in your notebook to record the results of measurements and calculations:

I , BUT	I Wed , BUT	m, kg	t, with	e, cl
I 1 = ; I 2 = ; I 3 = ; I 4 = ; I 5 = ; I 6 = ; I 7 = ; I 8 = ; I 9 = ; I 10 = ; I 11 = ; I 12 = ; I 13 = ; I 14 =; I 15 = ;

Measure the mass m 1 of the electrode, which will later be connected to the negative pole of the power supply.

Assemble the electrical circuit. The electrodes are connected to the circuit by inserting their bent petals into the slots of the plugs of the connecting wires.

Check the correct assembly of the chain and the reliability of the fastening of the connecting leads.

Connect the power supply to the mains and fill the cuvette with copper sulphate solution.

Close the key and at the same time start the countdown. Record the first reading of the ammeter I 1

For 15-20 minutes at intervals of one minute, measure and record the magnitude of the current in the circuit.

After 15-20 minutes from the moment the key is closed, open it, turn off the power supply and disassemble the circuit.

Rinse and dry the cathode.

Calculate the average value of the current I cf.

Measure the mass of the cathode t 2 .

Calculate the mass of copper deposited on the cathode: m \u003d m 1 - m 2.

Determine by formula (1) the value of the electron charge.

Observation of the effect of a magnetic field on current

Objective: experimentally determine the dependence of the action of a magnetic field on a current-carrying conductor on the strength and direction of the current in it.

Equipment: power supply, coil-coil, variable resistor, key, bar magnet, tripod with clutch and foot, connecting wires.

In this paper, we study the interaction of a wire coil suspended on a tripod with a permanent magnet, also installed on this tripod next to the coil. A variable resistance is switched on in series with the coil, which allows you to change the current strength in it during the experiment. Wiring diagram installation is shown in Figure 1.

experience number

D , diopter

D, diopter

By changing the connection of the connecting leads to the power source, establish how the effect of the magnetic field on the coil depends on the direction of the current in it.

Reverse the position of the magnet poles and repeat steps 3, 4 and 5.

For each stage of the experiment, make schematic drawings that reflect changes in the interaction between the magnet and the coil when changing the operating modes of the installation.

Indicate in the figures the directions of the magnetic field of the magnet, the current in the coil and the magnetic field of the coil.

Explain the results of the observations.