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 alpha particle moves at 1.5 × 10⁶ m/s at an angle of 60° to a uniform magnetic field of 0.8 T. Find the magnitude of the magnetic force F on it.

|q| = 3.204 × 10⁻¹⁹ Cv = 1.5 × 10⁶ m/sB = 0.8 Tθ = 60°

F = fN

2.Easy

A long straight wire carries a current of 40 A. Find the magnetic flux density B at point P, 2 cm from the wire.

I = 40 Ar = 2 cmμ₀ = 4π × 10⁻⁷ T·m/A

B = µT

3.Medium

A square loop moves to the right into a region with a uniform magnetic field pointing into the page. Click the direction of the induced current in the loop as seen in the drawing, while the loop is entering the field.

B: into the pageentering the field

1clockwise
2counterclockwise

4.Medium

A proton moving at 8 × 10⁶ m/s enters a uniform magnetic field at right angles and moves on a circle of radius 33.42 cm. Find the magnetic flux density B.

m = 1.673 × 10⁻²⁷ kg|q| = 1.602 × 10⁻¹⁹ Cv = 8 × 10⁶ m/sr = 33.42 cm

B = T

5.Hard

A coil of 20 turns, 8 cm × 5 cm, rotates at 3600 rpm in a uniform field of 0.05 T about an axis perpendicular to the field. Find the rms value E_rms of the emf.

N = 20A = 8 cm × 5 cmB = 0.05 Tn = 3600 rpm

E_rms = V

6.Hard

The current in a 50 mH inductor changes steadily from 0.5 A to 5.5 A in 2 ms. Find the magnitude of the self-induced emf ε.

L = 50 mH0.5 A → 5.5 AΔt = 2 ms

ε = V

Answer key

1. F = 333 fN
2. B = 400 µT
3. counterclockwise
4. B = 0.25 T
5. E_rms = 1.066 V
6. ε = 125 V

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