Quick answer: Electromagnetic induction is the creation of an emf in a circuit when the magnetic flux linked with it changes. This Physics 11-12 test on electromagnetic induction has 8 questions worth 20 marks, to do in 45 minutes: defining flux, tilted coil and Faraday’s law. The mark scheme is on a separate page; free printable PDF.
This test covers flux, Faraday’s and Lenz’s laws, moving conductors and generators. Show formulas, substitutions and units. Calculators are allowed. Use g = 9.81 N/kg where needed.
Level: Physics grades 11-12 (A Level · IB · Class 11-12) · Curriculum: IB D.4
Question 2 Tilted coil (2 marks)
A coil of area 0.030 m² is in a 0.25 T field. The normal to the coil makes an angle of 40° with the field. Calculate the flux through the coil.
Question 3 Faraday’s law (3 marks)
The flux through each turn of a 400-turn coil falls from 3.0 mWb to zero in 0.15 s.
- State Faraday’s law. (1 mark)
- Calculate the average emf induced in the coil. (2 marks)
Question 4 Lenz’s law (3 marks)
The north pole of a bar magnet is pulled away from a coil.
- State the polarity of the end of the coil nearest the magnet. (1 mark)
- Explain this using conservation of energy. (2 marks)
Question 5 Sliding rod (3 marks)
A rod 0.45 m long moves at 1.8 m/s perpendicular to a 0.35 T field in a circuit of resistance 0.20 Ω. Calculate the emf and the current.
Question 6 Reading a generator graph (3 marks)
The graph shows the emf from a small generator.
- State the peak emf and the period. (1 mark)
- Calculate the frequency and the angular speed. (2 marks)
Question 7 Open and closed coil (2 marks)
Explain why it is harder to push a magnet into a closed coil than into an open one.
Question 8 Falling magnet (2 marks)
A magnet falls through a coil and a larger pulse is recorded as it leaves than as it enters. Explain this.
