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 proton moves at 5 × 10⁶ m/s perpendicular to a uniform magnetic field of 0.05 T. Find the magnitude of the magnetic force F on it.

|q| = 1.602 × 10⁻¹⁹ Cv = 5 × 10⁶ m/sB = 0.05 Tθ = 90°

F = fN

2.Easy

A straight wire 100 cm long lies at 90° to a uniform magnetic field of 0.05 T. The magnetic force on it is 0.5 N. Find the current I.

B = 0.05 TF = 0.5 NL = 100 cmθ = 90°

I = A

3.Medium

A coil of 100 turns has an area of 40 cm². The coil sits in a uniform field of 0.2 T perpendicular to its plane, and the field is switched off in 50 ms. Find the average induced emf ε.

N = 100A = 40 cm²B = 0.2 TΔt = 50 ms

ε = V

4.Medium

A coil of 100 turns has an area of 25 cm². The coil is turned over (rotated through 180°) in a uniform field of 0.8 T, which is perpendicular to its plane, in 100 ms. Find the average induced emf ε.

N = 100A = 25 cm²B = 0.8 TΔt = 100 ms

ε = V

5.Hard

A deuteron starts from rest, is accelerated through a potential difference of 5000 V and then enters a uniform magnetic field of 0.4 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 = 5000 VB = 0.4 T

r = cm

6.Hard

In a velocity selector, crossed fields E = 8 × 10⁴ V/m and B = 0.05 T let only ions of one speed pass straight through. Find that speed v.

E = 8 × 10⁴ V/mB₁ = 0.05 T

v = m/s

Answer key

1. F = 40.05 fN
2. I = 10 A
3. ε = 1.6 V
4. ε = 4 V
5. r = 3.612 cm
6. v = 1.6 × 10⁶ m/s

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