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
B0.08 T2 A60°L = 20 cm

A straight wire 20 cm long carries 2 A at an angle of 60° to a uniform magnetic field of 0.08 T. Find the magnitude of the force F on the wire.

B = 0.08 TI = 2 AL = 20 cmθ = 60°
F = N
2.Easy
I = ?Pr = 5 cmB = 60 µT

The magnetic flux density 5 cm from a long straight wire is 60 µT. Find the current I in the wire.

B = 60 µTr = 5 cmμ₀ = 4π × 10⁻⁷ T·m/A
I = A
3.Medium
dB/dt < 0I = ?

A circular loop lies in a uniform magnetic field pointing out of the page. The field strength is decreasing. Click the direction of the induced current in the loop as seen in the drawing.

B: out of the pagedB/dt < 0
  1. 1clockwise
  2. 2counterclockwise
4.Medium
−v = 1 × 10⁶ m/sr = ?B = 10 mT

An electron moves at 1 × 10⁶ m/s perpendicular to a uniform magnetic field of 10 mT. Find the radius r of its circular path.

m = 9.109 × 10⁻³¹ kg|q| = 1.602 × 10⁻¹⁹ Cv = 1 × 10⁶ m/sB = 10 mT
r = cm
5.Hard
l = 25 cmN = 2000, ⌀ 4 cm

A long air-core solenoid has 2000 turns, a length of 25 cm and a diameter of 4 cm. Find its self-inductance L.

N = 2000l = 25 cm⌀ = 4 cmμ₀ = 4π × 10⁻⁷ T·m/A
L = mH
6.Hard
l = 10 cmN = 2000, ⌀ 2.5 cm

A long air-core solenoid has 2000 turns, a length of 10 cm and a diameter of 2.5 cm. Find its self-inductance L.

N = 2000l = 10 cm⌀ = 2.5 cmμ₀ = 4π × 10⁻⁷ T·m/A
L = mH

Answer key

  1. 1. F = 0.02771 N
  2. 2. I = 15 A
  3. 3. counterclockwise
  4. 4. r = 0.05686 cm
  5. 5. L = 25.27 mH
  6. 6. L = 24.67 mH

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