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
−v = 1.5 × 10⁵ m/sB = 1.5 T

An electron moves at 1.5 × 10⁵ m/s perpendicular to a uniform magnetic field of 1.5 T. Find the magnitude of the magnetic force F on it.

|q| = 1.602 × 10⁻¹⁹ Cv = 1.5 × 10⁵ m/sB = 1.5 Tθ = 90°
F = fN
2.Easy
+v = 6 × 10⁶ m/sB = 1 T

A proton moves at 6 × 10⁶ m/s at an angle of 45° to a uniform magnetic field of 1 T. Find the magnitude of the magnetic force F on it.

|q| = 1.602 × 10⁻¹⁹ Cv = 6 × 10⁶ m/sB = 1 Tθ = 45°
F = fN
3.Medium
+v = 1.5 × 10⁶ m/sr = 12.44 cmB = ?

An alpha particle moving at 1.5 × 10⁶ m/s enters a uniform magnetic field at right angles and moves on a circle of radius 12.44 cm. Find the magnetic flux density B.

m = 6.645 × 10⁻²⁷ kg|q| = 3.204 × 10⁻¹⁹ Cv = 1.5 × 10⁶ m/sr = 12.44 cm
B = T
4.Medium
IBF = ?

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

I: up the pageB: out of the page
  1. 1up the page
  2. 2to the right
  3. 3down the page
  4. 4to the left
5.Hard
E = 2 × 10⁵ V/m, B1​ = 0.1 T

In a velocity selector, crossed fields E = 2 × 10⁵ V/m and B = 0.1 T let only ions of one speed pass straight through. Find that speed v.

E = 2 × 10⁵ V/mB1 = 0.1 T
v = m/s
6.Hard
L = 50 mH4.5 → 0.5 A

The current in a 50 mH inductor changes steadily from 4.5 A to 0.5 A in 1 ms. Find the magnitude of the self-induced emf ε.

L = 50 mH4.5 A → 0.5 AΔt = 1 ms
ε = V

Answer key

  1. 1. F = 36.04 fN
  2. 2. F = 679.7 fN
  3. 3. B = 0.2501 T
  4. 4. to the right
  5. 5. v = 2 × 10⁶ m/s
  6. 6. ε = 200 V

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