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 T

An electron moves at 1.5 × 10⁵ m/s at an angle of 60° to a uniform magnetic field of 1 T. Find the magnitude of the magnetic force F on it.

|q| = 1.602 × 10⁻¹⁹ Cv = 1.5 × 10⁵ m/sB = 1 Tθ = 60°
F = fN
2.Easy
+v = 4 × 10⁵ m/sB = 0.5 T

A proton moves at 4 × 10⁵ m/s perpendicular to a uniform magnetic field of 0.5 T. Find the magnitude of the magnetic force F on it.

|q| = 1.602 × 10⁻¹⁹ Cv = 4 × 10⁵ m/sB = 0.5 Tθ = 90°
F = fN
3.Medium
−vBF = ?

An electron moves up the page through a uniform magnetic field pointing out of the page. Click the direction of the magnetic force on it.

v: up the pageB: out of the page
  1. 1up the page
  2. 2to the right
  3. 3down the page
  4. 4to the left
4.Medium
+v = 1 × 10⁶ m/sr = ?B = 0.1 T

An alpha particle moves at 1 × 10⁶ m/s perpendicular to a uniform magnetic field of 0.1 T. Find the radius r of its circular path.

m = 6.645 × 10⁻²⁷ kg|q| = 3.204 × 10⁻¹⁹ Cv = 1 × 10⁶ m/sB = 0.1 T
r = cm
5.Hard
E = 1 × 10⁴ V/m, B1​ = 0.25 TB2​ = 0.8 Tr = ?

A proton passes undeflected through a velocity selector with crossed fields E = 1 × 10⁴ V/m and B₁ = 0.25 T. It then enters a second region with only a magnetic field B₂ = 0.8 T, at right angles. Find the radius r of its path there.

E = 1 × 10⁴ V/mB1 = 0.25 TB2 = 0.8 Tm = 1.673 × 10⁻²⁷ kg|q| = 1.602 × 10⁻¹⁹ C
r = cm
6.Hard
l = 15 cmN = 800, ⌀ 2 cm

A long air-core solenoid has 800 turns, a length of 15 cm and a diameter of 2 cm. Find its self-inductance L.

N = 800l = 15 cm⌀ = 2 cmμ₀ = 4π × 10⁻⁷ T·m/A
L = mH

Answer key

  1. 1. F = 20.81 fN
  2. 2. F = 32.04 fN
  3. 3. to the left
  4. 4. r = 20.74 cm
  5. 5. r = 0.05222 cm
  6. 6. L = 1.684 mH

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