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 straight wire 25 cm long carries 1 A at an angle of 90° to a uniform magnetic field of 0.4 T. Find the magnitude of the force F on the wire.

B = 0.4 TI = 1 AL = 25 cmθ = 90°

F = N

2.Easy

A rectangular loop of 12 cm by 15 cm lies in a uniform magnetic field of 0.2 T. The field makes an angle of 0° with the normal of the loop. Find the magnetic flux Φ through the loop.

B = 0.2 TA = 12 cm × 15 cm0° to the normal

Φ = mWb

3.Medium

An electron moves at 2.5 × 10⁶ m/s perpendicular to a uniform magnetic field of 5 mT. Find the radius r of its circular path.

m = 9.109 × 10⁻³¹ kg|q| = 1.602 × 10⁻¹⁹ Cv = 2.5 × 10⁶ m/sB = 5 mT

r = cm

4.Medium

An alpha particle moves at 5 × 10⁶ m/s perpendicular to a uniform magnetic field of 1.5 T. Find the radius r of its circular path.

m = 6.645 × 10⁻²⁷ kg|q| = 3.204 × 10⁻¹⁹ Cv = 5 × 10⁶ m/sB = 1.5 T

r = cm

5.Hard

A coil of 250 turns, 5 cm × 25 cm, rotates in a uniform field of 0.3 T about an axis perpendicular to the field. At what speed n (in revolutions per minute) must it turn to give an rms emf of 41.65 V?

N = 250A = 5 cm × 25 cmB = 0.3 TE_rms = 41.65 V

n = rpm

6.Hard

A coil of 200 turns, 8 cm × 20 cm, rotates at 1500 rpm in a uniform field of 0.3 T about an axis perpendicular to the field. Find the rms value E_rms of the emf.

N = 200A = 8 cm × 20 cmB = 0.3 Tn = 1500 rpm

E_rms = V

Answer key

1. F = 0.1 N
2. Φ = 3.6 mWb
3. r = 0.2843 cm
4. r = 6.913 cm
5. n = 600 rpm
6. E_rms = 106.6 V

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