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.

New worksheetPractise online with hints

For teachers: free to print, copy and use in class. Every new worksheet has new values and its own answer key. A link to ExamProblems on your course page is appreciated.

Name: ____________________   Date: ____________

1.Easy
+v = 2.5 × 10⁶ m/sB = 0.05 T

An alpha particle moves at 2.5 × 10⁶ m/s at an angle of 60° to a uniform magnetic field of 0.05 T. Find the magnitude of the magnetic force F on it.

|q| = 3.204 × 10⁻¹⁹ Cv = 2.5 × 10⁶ m/sB = 0.05 Tθ = 60°
F = fN
2.Easy
+v = 5 × 10⁶ m/sB = 0.01 T

An alpha particle moves at 5 × 10⁶ m/s at an angle of 30° to a uniform magnetic field of 0.01 T. Find the magnitude of the magnetic force F on it.

|q| = 3.204 × 10⁻¹⁹ Cv = 5 × 10⁶ m/sB = 0.01 Tθ = 30°
F = fN
3.Medium
nBA = 20 cm², N = 100B = 0.5 T

A coil of 100 turns has an area of 20 cm². The coil is turned over (rotated through 180°) in a uniform field of 0.5 T, which is perpendicular to its plane, in 40 ms. Find the average induced emf ε.

N = 100A = 20 cm²B = 0.5 TΔt = 40 ms
ε = V
4.Medium
+v = 3 × 10⁶ m/sr = ?B = 0.4 T

An alpha particle moves at 3 × 10⁶ m/s perpendicular to a uniform magnetic field of 0.4 T. Find the radius r of its circular path.

m = 6.645 × 10⁻²⁷ kg|q| = 3.204 × 10⁻¹⁹ Cv = 3 × 10⁶ m/sB = 0.4 T
r = cm
5.Hard
Bn = ?12 cm × 5 cmN = 500B = 0.5 T

A coil of 500 turns, 12 cm × 5 cm, rotates in a uniform field of 0.5 T about an axis perpendicular to the field. At what speed n (in revolutions per minute) must it turn to give an rms emf of 166.6 V?

N = 500A = 12 cm × 5 cmB = 0.5 TErms = 166.6 V
n = rpm
6.Hard
Bn = 1800 rpm8 cm × 15 cmN = 250B = 0.3 T

A coil of 250 turns, 8 cm × 15 cm, rotates at 1800 rpm in a uniform field of 0.3 T about an axis perpendicular to the field. Find the rms value Erms of the emf.

N = 250A = 8 cm × 15 cmB = 0.3 Tn = 1800 rpm
Erms = V

Answer key

  1. 1. F = 34.68 fN
  2. 2. F = 8.01 fN
  3. 3. ε = 5 V
  4. 4. r = 15.55 cm
  5. 5. n = 1500 rpm
  6. 6. Erms = 120 V

Full step-by-step solutions: practise this topic on examproblems.com.