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 long straight wire carries a current of 15 A. Find the magnetic flux density B at point P, 1 cm from the wire.

I = 15 Ar = 1 cmμ₀ = 4π × 10⁻⁷ T·m/A

B = µT

2.Easy

An alpha particle moves at 2 × 10⁵ m/s at an angle of 30° to a uniform magnetic field of 0.8 T. Find the magnitude of the magnetic force F on it.

|q| = 3.204 × 10⁻¹⁹ Cv = 2 × 10⁵ m/sB = 0.8 Tθ = 30°

F = fN

3.Medium

A proton moves to the left through a uniform magnetic field pointing out of the page. Click the direction of the magnetic force on it.

v: to the leftB: out of the page

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

4.Medium

A circular loop lies in a uniform magnetic field pointing out of the page. The field strength is increasing. Click the direction of the induced current in the loop as seen in the drawing.

B: out of the pagedB/dt > 0

1clockwise
2counterclockwise

5.Hard

A long air-core solenoid has 2000 turns, a length of 40 cm and a diameter of 1 cm. Find the energy W stored in its magnetic field when it carries 5 A.

N = 2000l = 40 cm⌀ = 1 cmI = 5 Aμ₀ = 4π × 10⁻⁷ T·m/A

W = mJ

6.Hard

A long air-core solenoid has 2000 turns, a length of 20 cm and a diameter of 5 cm. Find its self-inductance L.

N = 2000l = 20 cm⌀ = 5 cmμ₀ = 4π × 10⁻⁷ T·m/A

L = mH

Answer key

1. B = 300 µT
2. F = 25.63 fN
3. up the page
4. clockwise
5. W = 12.34 mJ
6. L = 49.35 mH

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