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
B = ?I = 1 AL = 20 cmN = 250

A solenoid 20 cm long has 250 turns and carries 1 A. Find the magnetic flux density B inside it, far from the ends.

N = 250L = 20 cmI = 1 Aμ₀ = 4π × 10⁻⁷ T·m/A
B = mT
2.Easy
+v = 3 × 10⁶ m/sB = 0.01 T

An alpha particle moves at 3 × 10⁶ m/s at an angle of 45° 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 = 3 × 10⁶ m/sB = 0.01 Tθ = 45°
F = fN
3.Medium
+vBF = ?

A proton 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 = 1.5 × 10⁶ m/sr = ?B = 8 mT

An electron moves at 1.5 × 10⁶ m/s perpendicular to a uniform magnetic field of 8 mT. Find the radius r of its circular path.

m = 9.109 × 10⁻³¹ kg|q| = 1.602 × 10⁻¹⁹ Cv = 1.5 × 10⁶ m/sB = 8 mT
r = cm
5.Hard
L1​ = 80 mH500 A/sL2​ = 50 mHk = 0.8ε = ?

Two coils with self-inductances of 80 mH and 50 mH have a coupling coefficient of 0.8. The current in the first coil changes at 500 A/s. Find the emf ε induced in the second coil.

L1 = 80 mHL2 = 50 mHk = 0.8di/dt = 500 A/s
ε = V
6.Hard
V = 5000 VB = 0.5 Tr = ?

A proton starts from rest, is accelerated through a potential difference of 5000 V and then enters a uniform magnetic field of 0.5 T at right angles. Find the radius r of its path in the field.

m = 1.673 × 10⁻²⁷ kg|q| = 1.602 × 10⁻¹⁹ CV = 5000 VB = 0.5 T
r = cm

Answer key

  1. 1. B = 1.571 mT
  2. 2. F = 6.797 fN
  3. 3. to the right
  4. 4. r = 0.1066 cm
  5. 5. ε = 25.3 V
  6. 6. r = 2.044 cm

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