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 flat circular coil of 5 turns and radius 3 cm carries a current of 5 A. Find the magnetic flux density B at its centre.

N = 5I = 5 AR = 3 cmμ₀ = 4π × 10⁻⁷ T·m/A

B = µT

2.Easy

An electron moves at 5 × 10⁶ 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| = 1.602 × 10⁻¹⁹ Cv = 5 × 10⁶ m/sB = 0.2 Tθ = 45°

F = fN

3.Medium

A wire carries a current to the left through a uniform magnetic field pointing out of the page. Click the direction of the magnetic force on the wire.

I: to the leftB: out of the page

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

4.Medium

A metal rod 50 cm long slides at 10 m/s along two rails in a uniform field of 0.5 T into the page. Find the induced emf ε between its ends.

B = 0.5 TL = 50 cmv = 10 m/s

ε = V

5.Hard

A short coil of 200 turns is wound tightly round the middle of a long solenoid of 800 turns, length 25 cm and diameter 4 cm. Find their mutual inductance M.

N₁ = 800N₂ = 200l = 25 cm⌀ = 4 cmμ₀ = 4π × 10⁻⁷ T·m/A

M = mH

6.Hard

A long air-core solenoid has 1500 turns, a length of 50 cm and a diameter of 2 cm. Find its self-inductance L.

N = 1500l = 50 cm⌀ = 2 cmμ₀ = 4π × 10⁻⁷ T·m/A

L = mH

Answer key

1. B = 523.6 µT
2. F = 113.3 fN
3. up the page
4. ε = 2.5 V
5. M = 1.011 mH
6. L = 1.777 mH

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