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
I = 0.5 AR = 5 cmB = ?N = 100

A flat circular coil of 100 turns and radius 5 cm carries a current of 0.5 A. Find the magnetic flux density B at its centre.

N = 100I = 0.5 AR = 5 cmμ₀ = 4π × 10⁻⁷ T·m/A
B = µT
2.Easy
I = 4 APr = 20 cmB = ?

A long straight wire carries a current of 4 A. Find the magnetic flux density B at point P, 20 cm from the wire.

I = 4 Ar = 20 cmμ₀ = 4π × 10⁻⁷ T·m/A
B = µT
3.Medium
IBF = ?

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

I: up the pageB: into the page
  1. 1up the page
  2. 2to the right
  3. 3down the page
  4. 4to the left
4.Medium
−vBF = ?

An electron moves down the page through a uniform magnetic field pointing out of the page. Click the direction of the magnetic force on it.

v: 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 = 2000 VB = 0.1 Tr = ?

A proton starts from rest, is accelerated through a potential difference of 2000 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 = 2000 VB = 0.1 T
r = cm
6.Hard
V = 500 VB = 0.4 Tr = ?

A deuteron starts from rest, is accelerated through a potential difference of 500 V and then enters a uniform magnetic field of 0.4 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 = 500 VB = 0.4 T
r = cm

Answer key

  1. 1. B = 628.3 µT
  2. 2. B = 4 µT
  3. 3. to the left
  4. 4. to the right
  5. 5. r = 6.463 cm
  6. 6. r = 1.142 cm

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