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 40 cm long carries 6 A at an angle of 30° to a uniform magnetic field of 0.5 T. Find the magnitude of the force F on the wire.

B = 0.5 TI = 6 AL = 40 cmθ = 30°

F = N

2.Easy

A straight wire 50 cm long carries 15 A at an angle of 60° to a uniform magnetic field of 1.2 T. Find the magnitude of the force F on the wire.

B = 1.2 TI = 15 AL = 50 cmθ = 60°

F = N

3.Medium

A coil of 50 turns, area 10 cm² and resistance 10 Ω forms a closed circuit. A uniform field perpendicular to the coil rises steadily from 0.2 T to 0.6 T in 20 ms. Find the average induced current I.

N = 50A = 10 cm²B: 0.2 T → 0.6 TΔt = 20 msR = 10 Ω

I = mA

4.Medium

An alpha particle moves at 1 × 10⁶ m/s perpendicular to a uniform magnetic field of 0.2 T. Find the radius r of its circular path.

m = 6.645 × 10⁻²⁷ kg|q| = 3.204 × 10⁻¹⁹ Cv = 1 × 10⁶ m/sB = 0.2 T

r = cm

5.Hard

A long air-core solenoid has 200 turns, a length of 25 cm and a diameter of 1 cm. Find its self-inductance L.

N = 200l = 25 cm⌀ = 1 cmμ₀ = 4π × 10⁻⁷ T·m/A

L = µH

6.Hard

A long air-core solenoid has 2000 turns, a length of 30 cm and a diameter of 2.5 cm. Find the energy W stored in its magnetic field when it carries 3 A.

N = 2000l = 30 cm⌀ = 2.5 cmI = 3 Aμ₀ = 4π × 10⁻⁷ T·m/A

W = mJ

Answer key

1. F = 0.6 N
2. F = 7.794 N
3. I = 100 mA
4. r = 10.37 cm
5. L = 15.79 µH
6. W = 37.01 mJ

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