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

An alpha particle moves at 8 × 10⁶ m/s at an angle of 45° to a uniform magnetic field of 0.8 T. Find the magnitude of the magnetic force F on it.

|q| = 3.204 × 10⁻¹⁹ Cv = 8 × 10⁶ m/sB = 0.8 Tθ = 45°

F = pN

2.Easy

A solenoid 40 cm long has 1500 turns and carries 2.5 A. Find the magnetic flux density B inside it, far from the ends.

N = 1500L = 40 cmI = 2.5 Aμ₀ = 4π × 10⁻⁷ T·m/A

B = mT

3.Medium

A metal rod 50 cm long slides at 3 m/s along two rails in a uniform field of 0.25 T into the page. The rails are joined by a resistor of 0.5 Ω; the rod and rails have negligible resistance. Find the power P dissipated in the resistor.

B = 0.25 TL = 50 cmv = 3 m/sR = 0.5 Ω

P = mW

4.Medium

A coil of 250 turns has an area of 200 cm². The coil is turned over (rotated through 180°) in a uniform field of 0.8 T, which is perpendicular to its plane, in 500 ms. Find the average induced emf ε.

N = 250A = 200 cm²B = 0.8 TΔt = 500 ms

ε = V

5.Hard

In a velocity selector, crossed fields E = 1 × 10⁵ V/m and B = 0.4 T let only ions of one speed pass straight through. Find that speed v.

E = 1 × 10⁵ V/mB₁ = 0.4 T

v = m/s

6.Hard

A long air-core solenoid has 500 turns, a length of 50 cm and a diameter of 1 cm. Find its self-inductance L.

N = 500l = 50 cm⌀ = 1 cmμ₀ = 4π × 10⁻⁷ T·m/A

L = µH

Answer key

1. F = 1.45 pN
2. B = 11.78 mT
3. P = 281.3 mW
4. ε = 16 V
5. v = 250000 m/s
6. L = 49.35 µH

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