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

An electron moves at 1 × 10⁶ m/s perpendicular to a uniform magnetic field of 0.02 T. Find the magnitude of the magnetic force F on it.

|q| = 1.602 × 10⁻¹⁹ Cv = 1 × 10⁶ m/sB = 0.02 Tθ = 90°

F = fN

2.Easy

A rectangular loop of 5 cm by 15 cm lies in a uniform magnetic field of 0.05 T. The field makes an angle of 60° with the normal of the loop. Find the magnetic flux Φ through the loop.

B = 0.05 TA = 5 cm × 15 cm60° to the normal

Φ = mWb

3.Medium

A coil of 25 turns has an area of 20 cm². The coil is turned over (rotated through 180°) in a uniform field of 0.3 T, which is perpendicular to its plane, in 500 ms. Find the average induced emf ε.

N = 25A = 20 cm²B = 0.3 TΔt = 500 ms

ε = mV

4.Medium

A metal rod 25 cm long slides at 5 m/s along two rails in a uniform field of 1 T into the page. Find the induced emf ε between its ends.

B = 1 TL = 25 cmv = 5 m/s

ε = V

5.Hard

Two coils with self-inductances of 10 mH and 200 mH have a coupling coefficient of 0.4. The current in the first coil changes at 50 A/s. Find the emf ε induced in the second coil.

L₁ = 10 mHL₂ = 200 mHk = 0.4di/dt = 50 A/s

ε = V

6.Hard

A coil of 500 turns, 5 cm × 5 cm, rotates at 1500 rpm in a uniform field of 0.25 T about an axis perpendicular to the field. Find the rms value E_rms of the emf.

N = 500A = 5 cm × 5 cmB = 0.25 Tn = 1500 rpm

E_rms = V

Answer key

1. F = 3.204 fN
2. Φ = 0.1875 mWb
3. ε = 60 mV
4. ε = 1.25 V
5. ε = 0.8944 V
6. E_rms = 34.71 V

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