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 10 cm long carries 6 A at an angle of 90° to a uniform magnetic field of 0.4 T. Find the magnitude of the force F on the wire.

B = 0.4 TI = 6 AL = 10 cmθ = 90°

F = N

2.Easy

The magnetic flux density 3 cm from a long straight wire is 133.3 µT. Find the current I in the wire.

B = 133.3 µTr = 3 cmμ₀ = 4π × 10⁻⁷ T·m/A

I = A

3.Medium

A coil of 200 turns, area 150 cm² and resistance 8 Ω forms a closed circuit. A uniform field perpendicular to the coil rises steadily from 0.1 T to 0.7 T in 20 ms. Find the average induced current I.

N = 200A = 150 cm²B: 0.1 T → 0.7 TΔt = 20 msR = 8 Ω

I = A

4.Medium

A coil of 10 turns, area 80 cm² and resistance 4 Ω forms a closed circuit. A uniform field perpendicular to the coil rises steadily from 0.05 T to 0.15 T in 10 ms. Find the average induced current I.

N = 10A = 80 cm²B: 0.05 T → 0.15 TΔt = 10 msR = 4 Ω

I = mA

5.Hard

A coil of 200 turns, 20 cm × 10 cm, rotates at 900 rpm in a uniform field of 0.4 T about an axis perpendicular to the field. Find the peak emf E₀.

N = 200A = 20 cm × 10 cmB = 0.4 Tn = 900 rpm

E₀ = V

6.Hard

A deuteron starts from rest, is accelerated through a potential difference of 500 V and then enters a uniform magnetic field of 0.25 T at right angles. Find the radius r of its path in the field.

m = 3.344 × 10⁻²⁷ kg|q| = 1.602 × 10⁻¹⁹ CV = 500 VB = 0.25 T

r = cm

Answer key

1. F = 0.24 N
2. I = 20 A
3. I = 11.25 A
4. I = 200 mA
5. E₀ = 150.8 V
6. r = 1.828 cm

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