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
nB45°15 cm × 20 cmB = 0.6 T

A rectangular loop of 15 cm by 20 cm lies in a uniform magnetic field of 0.6 T. The field makes an angle of 45° with the normal of the loop. Find the magnetic flux Φ through the loop.

B = 0.6 TA = 15 cm × 20 cm45° to the normal
Φ = mWb
2.Easy
nB37°15 cm × 25 cmB = 0.2 T

A rectangular loop of 15 cm by 25 cm lies in a uniform magnetic field of 0.2 T. The field makes an angle of 37° with the normal of the loop. Find the magnetic flux Φ through the loop.

B = 0.2 TA = 15 cm × 25 cm37° to the normal
Φ = mWb
3.Medium
nBA = 25 cm², N = 20B: 0.2 → 0.5 T

A coil of 20 turns has an area of 25 cm². A uniform field perpendicular to the coil rises steadily from 0.2 T to 0.5 T in 200 ms. Find the average induced emf ε.

N = 20A = 25 cm²B: 0.2 T → 0.5 TΔt = 200 ms
ε = mV
4.Medium
IBF = ?

A wire carries a current down the page through a uniform magnetic field pointing into the page. Click the direction of the magnetic force on the wire.

I: down the pageB: into the page
  1. 1up the page
  2. 2to the right
  3. 3down the page
  4. 4to the left
5.Hard
l = 30 cmN = 100, ⌀ 1 cm

A long air-core solenoid has 100 turns, a length of 30 cm and a diameter of 1 cm. Find its self-inductance L.

N = 100l = 30 cm⌀ = 1 cmμ₀ = 4π × 10⁻⁷ T·m/A
L = µH
6.Hard
L = 10 mH3.5 → 2 A

The current in a 10 mH inductor changes steadily from 3.5 A to 2 A in 50 ms. Find the magnitude of the self-induced emf ε.

L = 10 mH3.5 A → 2 AΔt = 50 ms
ε = V

Answer key

  1. 1. Φ = 12.73 mWb
  2. 2. Φ = 5.99 mWb
  3. 3. ε = 75 mV
  4. 4. to the right
  5. 5. L = 3.29 µH
  6. 6. ε = 0.3 V

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