Practice Electromagnetic Induction in Physics

Use these practice problems to test your method after reviewing the concept explanation and worked examples.

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Quick Recap

The process by which a changing magnetic flux through a conducting loop produces a voltage (electromotive force, EMF) across the conductor, which can drive a current around a closed circuit.

Push a magnet into a coil and current flows — the changing magnetic field 'induces' electricity. Pull it out and current flows the other way.

Showing a random 20 of 50 problems.

Example 1

hard

50

-turn coil of area

0.01\,\text{m}^2

rotates at

\omega = 60\,\text{rad/s}

in a

0.2\,\text{T}

field. Find the peak EMF.

Example 2

medium

40

-turn coil has flux per turn going from

0.05\,\text{Wb}

0.20\,\text{Wb}

0.3\,\text{s}

. Find the EMF.

Example 3

medium

A bar magnet's north pole is pushed into a coil. According to Lenz's law, what is the polarity of the induced current's magnetic field on the side facing the magnet?

Example 4

easy

A coil with constant flux through it. What is the induced EMF?

Example 5

easy

A loop has flux changing by

0.5\,\text{Wb}

0.25\,\text{s}

. Find the average induced EMF magnitude.

Example 6

medium

A coil with area

0.02\,\text{m}^2

and

100

turns is rotated from parallel to perpendicular to a

0.3\,\text{T}

field in

0.05\,\text{s}

. Find the average EMF.

Example 7

medium

A loop of area

0.04\,\text{m}^2

sits perpendicular to a field that grows from

0.2\,\text{T}

1.0\,\text{T}

0.4\,\text{s}

. Find the EMF.

Example 8

easy

In the flux formula

\Phi_B = BA\cos\theta

, what does

\theta

measure?

Example 9

medium

A coil's flux changes by

0.3

Wb and induces

6

V in a single loop. Find the time interval.

Example 10

easy

Name one way to change the flux through a fixed loop.

Example 11

easy

Write the formula for magnetic flux through a flat loop.

Example 12

medium

Why does a coil in a constant field produce no current even if the field is enormous?

Example 13

easy

A single loop has flux changing by

6

Wb in

2

s. Find the average EMF magnitude.

Example 14

medium

Field

B=0.5

T through a

0.2

^2

loop drops to zero in

0.1

s (perpendicular). Find the average EMF.

Example 15

easy

State Faraday's law in words for a single loop.

Example 16

hard

A rod of length

0.5\,\text{m}

slides at

6\,\text{m/s}

on rails in a

0.4\,\text{T}

field. Circuit resistance is

1.5\,\Omega

. Find the magnetic drag force on the rod.

Example 17

hard

A circular loop of radius

R = 0.2\,\text{m}

sits perpendicular to a uniform field

B(t) = (0.5 + 0.3t)\,\text{T}

. Find the induced EMF magnitude.

Example 18

medium

A loop area shrinks from

0.5

^2

0.1

^2

0.4

s in a steady

2

T field (perpendicular). Find the EMF.

Example 19

hard

A rectangular loop (

0.1 \text{ m} \times 0.2 \text{ m}

) moves at

5 \text{ m/s}

into a region with a uniform

0.3 \text{ T}

magnetic field. What EMF is induced as the loop enters the field?

Example 20

medium

A flat loop of area

0.1\,\text{m}^2

sits at

60^\circ

to a

0.5\,\text{T}

field (angle between

\vec B

and normal is

60^\circ

). Find the flux through it.

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Related Concepts

Magnetic Field Magnetic Force Faraday's Law Lenz's Law Generator