Free Printable electromagnetic induction

Worksheets

electromagnetic induction

Total questions: 43

Worksheet time: 30mins

Name

Class

Date

Electromagnetic induction is change in ___________________.

surface area

magnetic poles

magnetic flux

Voltage can be induced in a wire by

a. moving the wire near a magnet.

b. moving a magnet near the wire.

c. changing the current in a nearby wire.

d. all of these

___ Law says that the Induced current is proportional to the change of magnetic flux

Lenz'

Faraday's

Ampere's

A magnet can move in a coil of wire to produce electricity in which system?

Generator

Motor

Magnet

Transformer

Which description best applies to Lenz's Law?

An induced current occurs when a magnet passes through a tube.

When a change in magnetic field occurs to a coil the direction of current goes in the in the other direction to this change.

The direction of an induced current is such to align with the change that created it.

A magnet is a tube is always slowed by its magnetic field.

What happens to the galvanometer if the copper rod is moved upwards?

No change

Deflect to the right

Deflect to the left

Deflect to the right and left

Which activity will produce the highest current?

Move the magnet bar into the coil while the coil remains stationery

Move the coil into the magnet bar while the magnet remains stationery

Move the coil and magnet towards each other

Move the coil and magnet away from each other

Which action will increase the deflection of the galvanometer pointer?

The magnetic pole is reversed

The number of turns of coils is increased

The coil is made from insulated wire

The magnet is slowly pushed into the coil

The voltmeter is at 0 in this image. How would you manipulate the experiment to create electricity (measured in volts)?

Flip the magnet around so the North pole is facing out

Move the magnet back and forth

Take the magnet out

Add more coils around the paper cylinder

10.

Electromagnetic induction is taking place in this experiment. How much electricity is being produced?

-10 Volts

10 Volts

100 Volts

This question cannot be answered based on this image

11.

How could the experimenter increase the amount of electricity being induced by this experiment?

Increase the number of coils

Decrease the number of coils

Flip the magnet around

Nothing, the amount of electricity cannot be increased

12.

What is one way to increase the current in a wire?

Decrease the number of coils

Increase the number of coils

Move the magnet slower

Take the wire off of the magnet

13.

What benefit is gained by the addition of the iron core in an electromagnet?

It makes a strong magnet weaker

It makes a weak magnet stronger

There is no benefit at all

It lets currents interact with each other

14.

What is the magnetic flux linked with the plane?

BA cos $\theta$

BA sin $\theta$

2BA cos $\theta$

2BA sin $\theta$

15.

A coil of area 30 $cm^2$ and 50 turns is placed perpendicular to the magnetic field of flux density 0.7 T. What is the magnetic flux linked with the coil?

0.021 Wb

0.105 Wb

1050 Wb

1500 Wb

16.

A plane of area 25 $cm^2$ is placed in a magnetic field of flux density 1.2 T. If the plane is inclined at $30^{\degree}$ to the magnetic field, calculate the magnetic flux linked with the plane.

0.0015 Wb

0.0030 Wb

0.0026 Wb

0.0035 Wb

17.

If XY is the normal line to the plane of the coil, what is the ratio of

\frac{magnetic\ flux\ in\ \left(a\right)}{magnetic\ flux\ in\ \left(b\right)}

1:2

1:1

2:1

3:2

18.

A bar magnet is moved towards a solenoid. Which of the following statement is not true about the changes experienced by the solenoid?

The galvanometer deflects when the magnet is brought near to the solenoid.

The induced current flows from X to Y when the magnet is approaching the solenoid.

The galvanometer shows maximum deflection when the magnet is in the centre of the solenoid.

The solenoid at end P acts as North pole when the magnet is moved away from end P.

19.

If points C and M are connected by a conducting wire, which statement is not true about the metal rod?

The induced current flows from M to C.

The e.m.f. induced in the rod is B $l$ v.

The end C of the rod is positively charged.

The free electrons in the rod experiences upward magnetic force.

20.

If the current flows in the wire increases at a constant rate, which statement below is true about the induced current in the coil?

It is constant and is in the clock wise direction.

It is constant and is in the anticlockwise direction.

It increase with time and is in the clockwise direction.

It is zero.

21.

An e.m.f. is induced in the coil from right to left. Which of the following describes the current through the coil?

The current is constant and it moves from right to left.

The current is constant and it moves from left to right.

The current is increasing and it moves from left to righ.

The current is increasing and it moves from right to left.

22.

A solenoid of length $l$ and cross-sectional area A contains N turns of wire. Which of the following shows the self-inductance L of the solenoid?

$\frac{\mu_0N^2A}{l}$

$\frac{\mu_0N^2\pi r}{2}$

$\mu_0N^2\pi r$

$\mu_0N^2A$

23.

A solenoid of cross-sectional area 0.25 cm² and length 10 cm contains 200 turns of wire and the solenoid is air filled. Calculate the self-inductance L of the solenoid.

7.5 $\mu H$

9.6 $\mu H$

11 $\mu H$

13 $\mu H$

24.

When the current in a solenoid changes uniformly from -12.0 mA to 18.0 mA in 15.0 ms, a back-e.m.f. is induced in the solenoid. If the self-inductance of the solenoid is 3.97 H, what is the value of the back e.m.f.?

7.94 V

8.50 V

8.79 V

10.2 V

25.

At the instant when the current is 9.0 A, a magnetic flux of 2.5 $\times10^{-3}$ Wb is produced in a coil of 1000 turns. Calculate the energy stored in the coil.

10.3 J

11.3 J

22.5 J

40.5 J

26.

If $l=2.44\ m$ , $N_p$ =300, $N_s$ =100, A=1.26 $\times10^{-3}m^2$ and teh solenoid is air-filled, calculate the mutual inductance between the solenoids.

1.16 $\times10^{-4}$ H

4.75 $\times10^{-5}$ H

3.15 $\times10^{-5}$ H

1.95 $\times10^{-5}$ H

27.

If the current in the primary coil decreases uniformly from 12.0 A to zero in 58.0 ms and the e.m.f. induced in the secondary coil is 8.03 V, calculate the mutual inductance, M.

1.66 mH

38.8 mH

39.3 mH

40.5 mH

28.

A permanent magnet is quickly introduced into the center of an aluminum closed ring. With this ring ...

will be attracted to the magnet;

push away from the magnet;

remain stationary;

it will start to rotate about an axis passing through its center.

29.

What type of current is being produced?

Alternating

Direct

30.

If a secondary coil has 40 turns, and, a primary coil with 20 turns is charged with 50 V of potential difference, then potential difference in secondary coil would be

50 V in secondary coil

25 V in secondary coil

60 V in secondary coil

100 V in secondary coil

31.

Ratio of voltages is equal to ratio of

iron sheets in core

coil

number of turns in coil

all of above

32.

What is meant by a step down transformer?

One where the output voltage is the same as the input voltage.

One where the output voltage is larger than the input voltage.

One where the output voltage is smaller than the input voltage.

33.

What is the job of a transformer?

Change the current of a power supply

Change the potential difference (voltage) of a power supply

Adds a resistor

34.

What is the national grid?

A power station

A network of wires/cables to distribute power around the country.

A row of electrical transformers

35.

Write an equation to show that if a transformer is 100% efficient then the power in the secondary coil = power in the primary coil

Vp x Ip = Vs / Is

p.d. across x current in = p.d. across / current

primary coil primary coil = secondary coil in secondary

Vp x Ip = Vs x Is

p.d. across x current in = p.d. across x current

primary coil primary coil = secondary coil in secondary

36.

Which is the only type of current that will work with transformers?

Direct current

Alternating current

Resistance

37.

What is electromagnetic induction in a transformer?

The current in one coil (of the transformer) causes/induces a voltage (p.d.) in the second coil.

The voltage (p.d.) in one coil (of the transformer) causes/induces a voltage (p.d.) in the second coil.

38.

What is the equation for electrical power

Electrical power = current / p.d.

P = I / V

Electrical power = current x p.d.

P = I x V

Electrical power = current + p.d.

P = I + V

39.

Describe the structure of a transformer

Made of two coils of wire wound round an iron core

Made of wire coiled around a magnet

Made of 10 wires that are wrapped around a magnet

40.

What does a step-down transformer do?

Decreases voltage and increases current

Increases voltage and decreases current

Keeps the voltage and the current the same

41.

Transformer is device that

converts AC voltage to current

converts electrical energy to kinetic energy

converts AC voltage to a different level at the same amplitude

converts AC voltage to a different level at the same frequency

42.

A transformer consists of

Metal Core

Metal core and coiled wire

Metal core and polymer wire

Polymer core and metal wire

43.

How would flipping the magnet in this experiment change the current?

The current would not change

The current would go to the right

There would be no current

The current would go CRAZY

100 %

electromagnetic induction

Total questions: 43

Worksheet time: 30mins

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