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 proton moves at 6 × 10⁵ m/s at an angle of 60° to a uniform magnetic field of 0.5 T. Find the magnitude of the magnetic force F on it.

|q| = 1.602 × 10⁻¹⁹ Cv = 6 × 10⁵ m/sB = 0.5 Tθ = 60°

F = fN

2.Easy

An alpha particle moves at 2 × 10⁵ m/s at an angle of 45° to a uniform magnetic field of 0.2 T. Find the magnitude of the magnetic force F on it.

|q| = 3.204 × 10⁻¹⁹ Cv = 2 × 10⁵ m/sB = 0.2 Tθ = 45°

F = fN

3.Medium

A coil of 100 turns has an area of 50 cm². The coil sits in a uniform field of 0.5 T perpendicular to its plane, and the field is switched off in 40 ms. Find the average induced emf ε.

N = 100A = 50 cm²B = 0.5 TΔt = 40 ms

ε = V

4.Medium

An electron moves at 6 × 10⁶ m/s perpendicular to a uniform magnetic field of 1 mT. Find the radius r of its circular path.

m = 9.109 × 10⁻³¹ kg|q| = 1.602 × 10⁻¹⁹ Cv = 6 × 10⁶ m/sB = 1 mT

r = cm

5.Hard

A coil of 250 turns, 12 cm × 5 cm, rotates at 900 rpm in a uniform field of 0.1 T about an axis perpendicular to the field. Find the rms value E_rms of the emf.

N = 250A = 12 cm × 5 cmB = 0.1 Tn = 900 rpm

E_rms = V

6.Hard

A long air-core solenoid has 2000 turns, a length of 30 cm and a diameter of 2.5 cm. Find its self-inductance L.

N = 2000l = 30 cm⌀ = 2.5 cmμ₀ = 4π × 10⁻⁷ T·m/A

L = mH

Answer key

1. F = 41.62 fN
2. F = 9.062 fN
3. ε = 6.25 V
4. r = 3.412 cm
5. E_rms = 9.996 V
6. L = 8.225 mH

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