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.

New worksheet Practise online with hints

For teachers: free to print, copy and use in class. Every new worksheet has new values and its own answer key. A link to ExamProblems on your course page is appreciated.

Name: ____________________ Date: ____________

1.Easy

A rectangular loop of 15 cm by 15 cm lies in a uniform magnetic field of 0.6 T. The field makes an angle of 60° with the normal of the loop. Find the magnetic flux Φ through the loop.

B = 0.6 TA = 15 cm × 15 cm60° to the normal

Φ = mWb

2.Easy

A flat circular coil of 25 turns and radius 8 cm carries a current of 0.5 A. Find the magnetic flux density B at its centre.

N = 25I = 0.5 AR = 8 cmμ₀ = 4π × 10⁻⁷ T·m/A

B = µT

3.Medium

A metal rod 100 cm long slides at 3 m/s along two rails in a uniform field of 1 T into the page. Find the induced emf ε between its ends.

B = 1 TL = 100 cmv = 3 m/s

ε = V

4.Medium

A circular loop lies in a uniform magnetic field pointing out of the page. The field strength is decreasing. Click the direction of the induced current in the loop as seen in the drawing.

B: out of the pagedB/dt < 0

1clockwise
2counterclockwise

5.Hard

A short coil of 100 turns is wound tightly round the middle of a long solenoid of 1500 turns, length 50 cm and diameter 3 cm. The current in the solenoid changes at 10 A/s. Find the emf ε induced in the short coil.

N₁ = 1500N₂ = 100l = 50 cm⌀ = 3 cmdi/dt = 10 A/sμ₀ = 4π × 10⁻⁷ T·m/A

ε = mV

6.Hard

A long air-core solenoid has 300 turns, a length of 50 cm and a diameter of 4 cm. Find the energy W stored in its magnetic field when it carries 3 A.

N = 300l = 50 cm⌀ = 4 cmI = 3 Aμ₀ = 4π × 10⁻⁷ T·m/A

W = mJ

Answer key

1. Φ = 6.75 mWb
2. B = 98.17 µT
3. ε = 3 V
4. counterclockwise
5. ε = 2.665 mV
6. W = 1.279 mJ

Full step-by-step solutions: practise this topic on examproblems.com.