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 flat circular coil of 50 turns and radius 2 cm carries a current of 3 A. Find the magnetic flux density B at its centre.

N = 50I = 3 AR = 2 cmμ₀ = 4π × 10⁻⁷ T·m/A

B = mT

2.Easy

A proton moves at 5 × 10⁶ m/s at an angle of 30° to a uniform magnetic field of 0.01 T. Find the magnitude of the magnetic force F on it.

|q| = 1.602 × 10⁻¹⁹ Cv = 5 × 10⁶ m/sB = 0.01 Tθ = 30°

F = fN

3.Medium

An alpha particle moves at 4 × 10⁵ m/s perpendicular to a uniform magnetic field of 0.25 T. Find the radius r of its circular path.

m = 6.645 × 10⁻²⁷ kg|q| = 3.204 × 10⁻¹⁹ Cv = 4 × 10⁵ m/sB = 0.25 T

r = cm

4.Medium

Two long parallel wires 2 cm apart carry currents of 25 A and 12 A in the same direction. Find the force per metre of length F/L between them.

I₁ = 25 AI₂ = 12 Ad = 2 cmμ₀ = 4π × 10⁻⁷ T·m/A

F/L = µN/m

5.Hard

A proton starts from rest, is accelerated through a potential difference of 10000 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 = 1.673 × 10⁻²⁷ kg|q| = 1.602 × 10⁻¹⁹ CV = 10000 VB = 0.3 T

r = cm

6.Hard

A long air-core solenoid has 100 turns, a length of 30 cm and a diameter of 1.5 cm. Find the energy W stored in its magnetic field when it carries 5 A.

N = 100l = 30 cm⌀ = 1.5 cmI = 5 Aμ₀ = 4π × 10⁻⁷ T·m/A

W = µJ

Answer key

1. B = 4.712 mT
2. F = 4.005 fN
3. r = 3.318 cm
4. F/L = 3000 µN/m
5. r = 4.817 cm
6. W = 92.53 µJ

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