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 = 1.5 × 10⁵ m/sB = 0.01 T

A proton moves at 1.5 × 10⁵ m/s at an angle of 30° to a uniform magnetic field of 0.01 T. Find the magnitude of the magnetic force F on it.

|q| = 1.602 × 10⁻¹⁹ Cv = 1.5 × 10⁵ m/sB = 0.01 Tθ = 30°
F = fN
2.Easy
I = 2 APr = ?B = 4 µT

A long straight wire carries 2 A. At what distance r from the wire is the magnetic flux density 4 µT?

I = 2 AB = 4 µTμ₀ = 4π × 10⁻⁷ T·m/A
r = cm
3.Medium
vI = ?

A square loop moves to the right into a region with a uniform magnetic field pointing into 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: into the pageentering the field
  1. 1clockwise
  2. 2counterclockwise
4.Medium
IBF = ?

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

I: to the rightB: into the page
  1. 1up the page
  2. 2to the right
  3. 3down the page
  4. 4to the left
5.Hard
l = 50 cmN = 200, ⌀ 2 cm

A long air-core solenoid has 200 turns, a length of 50 cm and a diameter of 2 cm. Find its self-inductance L.

N = 200l = 50 cm⌀ = 2 cmμ₀ = 4π × 10⁻⁷ T·m/A
L = µH
6.Hard
L = 5 mH0.5 → 2 A

The current in a 5 mH inductor changes steadily from 0.5 A to 2 A in 2 ms. Find the magnitude of the self-induced emf ε.

L = 5 mH0.5 A → 2 AΔt = 2 ms
ε = V

Answer key

  1. 1. F = 0.1201 fN
  2. 2. r = 10 cm
  3. 3. counterclockwise
  4. 4. up the page
  5. 5. L = 31.58 µH
  6. 6. ε = 3.75 V

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