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
B = ?I = 0.5 AL = 30 cmN = 400

A solenoid 30 cm long has 400 turns and carries 0.5 A. Find the magnetic flux density B inside it, far from the ends.

N = 400L = 30 cmI = 0.5 Aμ₀ = 4π × 10⁻⁷ T·m/A
B = mT
2.Easy
+v = 5 × 10⁶ m/sB = 1.5 T

A proton moves at 5 × 10⁶ m/s at an angle of 60° to a uniform magnetic field of 1.5 T. Find the magnitude of the magnetic force F on it.

|q| = 1.602 × 10⁻¹⁹ Cv = 5 × 10⁶ m/sB = 1.5 Tθ = 60°
F = pN
3.Medium
+vBF = ?

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

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

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

I: down the pageB: 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 = 0.1 Tr = ?

A proton starts from rest, is accelerated through a potential difference of 10000 V and then enters a uniform magnetic field of 0.1 T at right angles. Find the radius r of its path in the field.

m = 1.673 × 10⁻²⁷ kg|q| = 1.602 × 10⁻¹⁹ CV = 10000 VB = 0.1 T
r = cm
6.Hard
E = 4 × 10⁴ V/m, B1​ = 0.05 T

In a velocity selector, crossed fields E = 4 × 10⁴ V/m and B = 0.05 T let only ions of one speed pass straight through. Find that speed v.

E = 4 × 10⁴ V/mB1 = 0.05 T
v = m/s

Answer key

  1. 1. B = 0.8378 mT
  2. 2. F = 1.041 pN
  3. 3. to the right
  4. 4. to the left
  5. 5. r = 14.45 cm
  6. 6. v = 800000 m/s

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