Magnetic fields & induction worksheet with answers

Free printable Magnetic fields & induction worksheet: 6 problems from easy to exam level, with an answer key. Print it or save it as a PDF.

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1.Easy

A straight wire 15 cm long carries 1 A at an angle of 45° to a uniform magnetic field of 0.8 T. Find the magnitude of the force F on the wire.

B = 0.8 TI = 1 AL = 15 cmθ = 45°

F = N

2.Easy

A straight wire 10 cm long lies at 30° to a uniform magnetic field of 0.3 T. The magnetic force on it is 0.015 N. Find the current I.

B = 0.3 TF = 0.015 NL = 10 cmθ = 30°

I = A

3.Medium

An electron moves up the page through a uniform magnetic field pointing out of the page. Click the direction of the magnetic force on it.

v: up the pageB: out of the page

1up the page
2to the right
3down the page
4to the left

4.Medium

A square loop moves to the right into a region with a uniform magnetic field pointing out of the page. Click the direction of the induced current in the loop as seen in the drawing, while the loop is entering the field.

B: out of the pageentering the field

1clockwise
2counterclockwise

5.Hard

A short coil of 100 turns is wound tightly round the middle of a long solenoid of 2000 turns, length 30 cm and diameter 5 cm. Find their mutual inductance M.

N₁ = 2000N₂ = 100l = 30 cm⌀ = 5 cmμ₀ = 4π × 10⁻⁷ T·m/A

M = mH

6.Hard

A long air-core solenoid has 100 turns, a length of 50 cm and a diameter of 1 cm. Find the energy W stored in its magnetic field when it carries 3 A.

N = 100l = 50 cm⌀ = 1 cmI = 3 Aμ₀ = 4π × 10⁻⁷ T·m/A

W = µJ

Answer key

1. F = 0.08485 N
2. I = 1 A
3. to the left
4. clockwise
5. M = 1.645 mH
6. W = 8.883 µJ

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