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 rectangular loop of 10 cm by 10 cm lies in a uniform magnetic field of 0.2 T. The field lines make an angle of 30° with the plane of the loop. Find the magnetic flux Φ through the loop.

B = 0.2 TA = 10 cm × 10 cm30° to the plane

Φ = mWb

2.Easy

A straight wire 25 cm long carries 8 A at an angle of 90° to a uniform magnetic field of 0.1 T. Find the magnitude of the force F on the wire.

B = 0.1 TI = 8 AL = 25 cmθ = 90°

F = N

3.Medium

A proton moves down the page through a uniform magnetic field pointing into the page. Click the direction of the magnetic force on it.

v: down the pageB: into the page

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

4.Medium

An electron moves at 2 × 10⁶ m/s perpendicular to a uniform magnetic field of 10 mT. Find the radius r of its circular path.

m = 9.109 × 10⁻³¹ kg|q| = 1.602 × 10⁻¹⁹ Cv = 2 × 10⁶ m/sB = 10 mT

r = cm

5.Hard

A coil of 100 turns, 10 cm × 5 cm, rotates at 900 rpm in a uniform field of 0.4 T about an axis perpendicular to the field. Find the rms value E_rms of the emf.

N = 100A = 10 cm × 5 cmB = 0.4 Tn = 900 rpm

E_rms = V

6.Hard

The current in a 200 mH inductor changes steadily from 0 A to 2 A in 1 ms. Find the magnitude of the self-induced emf ε.

L = 200 mH0 A → 2 AΔt = 1 ms

ε = V

Answer key

1. Φ = 1 mWb
2. F = 0.2 N
3. to the right
4. r = 0.1137 cm
5. E_rms = 13.33 V
6. ε = 400 V

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