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
nB20°8 cm × 15 cmB = 0.1 T

A rectangular loop of 8 cm by 15 cm lies in a uniform magnetic field of 0.1 T. The field makes an angle of 20° with the normal of the loop. Find the magnetic flux Φ through the loop.

B = 0.1 TA = 8 cm × 15 cm20° to the normal
Φ = mWb
2.Easy
+v = 8 × 10⁵ m/sB = 0.05 T

An alpha particle moves at 8 × 10⁵ m/s at an angle of 60° to a uniform magnetic field of 0.05 T. Find the magnitude of the magnetic force F on it.

|q| = 3.204 × 10⁻¹⁹ Cv = 8 × 10⁵ m/sB = 0.05 Tθ = 60°
F = fN
3.Medium
IBF = ?

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

I: 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
nBA = 200 cm², N = 100B = 0.3 T

A coil of 100 turns has an area of 200 cm². The coil is turned over (rotated through 180°) in a uniform field of 0.3 T, which is perpendicular to its plane, in 200 ms. Find the average induced emf ε.

N = 100A = 200 cm²B = 0.3 TΔt = 200 ms
ε = V
5.Hard
E = 2 × 10⁵ V/m, B1​ = 0.2 TB2​ = 0.2 Tr = ?

A proton passes undeflected through a velocity selector with crossed fields E = 2 × 10⁵ V/m and B₁ = 0.2 T. It then enters a second region with only a magnetic field B₂ = 0.2 T, at right angles. Find the radius r of its path there.

E = 2 × 10⁵ V/mB1 = 0.2 TB2 = 0.2 Tm = 1.673 × 10⁻²⁷ kg|q| = 1.602 × 10⁻¹⁹ C
r = cm
6.Hard
I = 0.5 Al = 20 cmN = 2000, ⌀ 1.5 cm

A long air-core solenoid has 2000 turns, a length of 20 cm and a diameter of 1.5 cm. Find the energy W stored in its magnetic field when it carries 0.5 A.

N = 2000l = 20 cm⌀ = 1.5 cmI = 0.5 Aμ₀ = 4π × 10⁻⁷ T·m/A
W = µJ

Answer key

  1. 1. Φ = 1.128 mWb
  2. 2. F = 11.1 fN
  3. 3. down the page
  4. 4. ε = 6 V
  5. 5. r = 5.222 cm
  6. 6. W = 555.2 µJ

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