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 5 cm by 25 cm lies in a uniform magnetic field of 0.1 T. The field makes an angle of 0° with the normal of the loop. Find the magnetic flux Φ through the loop.

B = 0.1 TA = 5 cm × 25 cm0° to the normal

Φ = mWb

2.Easy

An electron moves at 3 × 10⁶ m/s at an angle of 45° to a uniform magnetic field of 0.1 T. Find the magnitude of the magnetic force F on it.

|q| = 1.602 × 10⁻¹⁹ Cv = 3 × 10⁶ m/sB = 0.1 Tθ = 45°

F = fN

3.Medium

An alpha particle moves at 3 × 10⁵ m/s perpendicular to a uniform magnetic field of 0.4 T. Find the radius r of its circular path.

m = 6.645 × 10⁻²⁷ kg|q| = 3.204 × 10⁻¹⁹ Cv = 3 × 10⁵ m/sB = 0.4 T

r = cm

4.Medium

A metal rod 20 cm long slides at 1 m/s along two rails in a uniform field of 1 T into the page. The rails are joined by a resistor of 10 Ω; the rod and rails have negligible resistance. Find the power P dissipated in the resistor.

B = 1 TL = 20 cmv = 1 m/sR = 10 Ω

P = mW

5.Hard

A long air-core solenoid has 200 turns, a length of 40 cm and a diameter of 5 cm. Find the energy W stored in its magnetic field when it carries 4 A.

N = 200l = 40 cm⌀ = 5 cmI = 4 Aμ₀ = 4π × 10⁻⁷ T·m/A

W = mJ

6.Hard

A coil of 500 turns, 12 cm × 10 cm, rotates at 3000 rpm in a uniform field of 0.1 T about an axis perpendicular to the field. Find the peak emf E₀.

N = 500A = 12 cm × 10 cmB = 0.1 Tn = 3000 rpm

E₀ = V

Answer key

1. Φ = 1.25 mWb
2. F = 33.98 fN
3. r = 1.555 cm
4. P = 4 mW
5. W = 1.974 mJ
6. E₀ = 188.5 V

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