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
I = 0.5 AR = 5 cmB = ?N = 10

A flat circular coil of 10 turns and radius 5 cm carries a current of 0.5 A. Find the magnetic flux density B at its centre.

N = 10I = 0.5 AR = 5 cmμ₀ = 4π × 10⁻⁷ T·m/A
B = µT
2.Easy
B = ?I = 1 AL = 25 cmN = 500

A solenoid 25 cm long has 500 turns and carries 1 A. Find the magnetic flux density B inside it, far from the ends.

N = 500L = 25 cmI = 1 Aμ₀ = 4π × 10⁻⁷ T·m/A
B = mT
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
−vBF = ?

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

v: to the leftB: out of the page
  1. 1up the page
  2. 2to the right
  3. 3down the page
  4. 4to the left
5.Hard
V = 10000 VB = 0.3 Tr = ?

A deuteron starts from rest, is accelerated through a potential difference of 10000 V and then enters a uniform magnetic field of 0.3 T at right angles. Find the radius r of its path in the field.

m = 3.344 × 10⁻²⁷ kg|q| = 1.602 × 10⁻¹⁹ CV = 10000 VB = 0.3 T
r = cm
6.Hard
Bn = 900 rpm10 cm × 5 cmN = 50B = 0.1 T

A coil of 50 turns, 10 cm × 5 cm, rotates at 900 rpm in a uniform field of 0.1 T about an axis perpendicular to the field. Find the peak emf E0.

N = 50A = 10 cm × 5 cmB = 0.1 Tn = 900 rpm
E0 = V

Answer key

  1. 1. B = 62.83 µT
  2. 2. B = 2.513 mT
  3. 3. down the page
  4. 4. down the page
  5. 5. r = 6.811 cm
  6. 6. E0 = 2.356 V

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