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 = 5 AL = 50 cmN = 250

A solenoid 50 cm long has 250 turns and carries 5 A. Find the magnetic flux density B inside it, far from the ends.

N = 250L = 50 cmI = 5 Aμ₀ = 4π × 10⁻⁷ T·m/A
B = mT
2.Easy
nB30°10 cm × 25 cmB = 0.6 T

A rectangular loop of 10 cm by 25 cm lies in a uniform magnetic field of 0.6 T. The field makes an angle of 30° with the normal of the loop. Find the magnetic flux Φ through the loop.

B = 0.6 TA = 10 cm × 25 cm30° to the normal
Φ = mWb
3.Medium
IBF = ?

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

I: 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
+v = 1 × 10⁵ m/sB = 0.8 T

A proton moves on a circle in a uniform magnetic field of 0.8 T. Find the time T it takes for one revolution.

m = 1.673 × 10⁻²⁷ kg|q| = 1.602 × 10⁻¹⁹ CB = 0.8 T
T = ns
5.Hard
I = 2.5 Al = 50 cmN = 2000, ⌀ 1 cm

A long air-core solenoid has 2000 turns, a length of 50 cm and a diameter of 1 cm. Find the energy W stored in its magnetic field when it carries 2.5 A.

N = 2000l = 50 cm⌀ = 1 cmI = 2.5 Aμ₀ = 4π × 10⁻⁷ T·m/A
W = mJ
6.Hard
V = 5000 VB = 0.3 Tr = ?

A deuteron starts from rest, is accelerated through a potential difference of 5000 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 = 5000 VB = 0.3 T
r = cm

Answer key

  1. 1. B = 3.142 mT
  2. 2. Φ = 12.99 mWb
  3. 3. to the right
  4. 4. T = 82.02 ns
  5. 5. W = 2.467 mJ
  6. 6. r = 4.816 cm

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