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 = 2.5 × 10⁶ m/sB = 0.05 T

An electron moves at 2.5 × 10⁶ m/s at an angle of 45° to a uniform magnetic field of 0.05 T. Find the magnitude of the magnetic force F on it.

|q| = 1.602 × 10⁻¹⁹ Cv = 2.5 × 10⁶ m/sB = 0.05 Tθ = 45°
F = fN
2.Easy
B1.2 T1 A90°L = 10 cm

A straight wire 10 cm long carries 1 A at an angle of 90° to a uniform magnetic field of 1.2 T. Find the magnitude of the force F on the wire.

B = 1.2 TI = 1 AL = 10 cmθ = 90°
F = N
3.Medium
+vBF = ?

A proton moves to the right through a uniform magnetic field pointing out of the page. Click the direction of the magnetic force on it.

v: to the rightB: out of the page
  1. 1up the page
  2. 2to the right
  3. 3down the page
  4. 4to the left
4.Medium
vI = ?

A square loop moves to the right into a region with a uniform magnetic field pointing out of the page. Click the direction of the induced current in the loop as seen in the drawing, while the loop is entering the field.

B: out of the pageentering the field
  1. 1clockwise
  2. 2counterclockwise
5.Hard
Bn = 1500 rpm8 cm × 5 cmN = 100B = 0.5 T

A coil of 100 turns, 8 cm × 5 cm, rotates at 1500 rpm in a uniform field of 0.5 T about an axis perpendicular to the field. Find the peak emf E0.

N = 100A = 8 cm × 5 cmB = 0.5 Tn = 1500 rpm
E0 = V
6.Hard
N1​ = 2000, l = 30 cm200 A/sN2​ = 200Mε = ?

A short coil of 200 turns is wound tightly round the middle of a long solenoid of 2000 turns, length 30 cm and diameter 4 cm. The current in the solenoid changes at 200 A/s. Find the emf ε induced in the short coil.

N1 = 2000N2 = 200l = 30 cm⌀ = 4 cmdi/dt = 200 A/sμ₀ = 4π × 10⁻⁷ T·m/A
ε = mV

Answer key

  1. 1. F = 14.16 fN
  2. 2. F = 0.12 N
  3. 3. down the page
  4. 4. clockwise
  5. 5. E0 = 31.42 V
  6. 6. ε = 421.1 mV

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