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Faraday’s law test with answers for AP Physics 2 (free PDF download)

Quick answer: Electromagnetic induction produces an emf whenever the magnetic flux Φ = BA cos θ through a loop changes. This AP Physics 2 test on faraday's law has 8 questions worth 20 marks, to do in 45 minutes: flux through a coil, induced emf and approaching south pole. The mark scheme is on a separate page; free printable PDF.

Faraday’s law test with answers for AP Physics 2 (free PDF download)

This test covers magnetic flux, Faraday’s law, Lenz’s law and motional emf. It lasts 45 minutes and is worth 20 points. A calculator is allowed. Show the formula, the substitution and the unit for each calculation.

Level: AP Physics 2 (algebra-based) · Curriculum: AP P2 Unit 12

Time: 45 minutes · 8 questions · Total: 20 marks · Calculator allowed

Question 1 Flux through a coil (2 marks)

A rectangular coil measures 12 cm by 8.0 cm. The coil is in a uniform field of 0.25 T, and the normal makes an angle of 40° with the field.

Calculate the magnetic flux through one turn. (2 marks)

Question 2 Induced emf (3 marks)

A coil of 300 turns has the flux through each turn fall from 4.0 mWb to 1.0 mWb in 0.050 s.

  1. Calculate the change in flux. (1 mark)
  2. Calculate the average emf. (1 mark)
  3. State what happens to the emf if the same change takes place in 0.025 s. (1 mark)

Question 3 Approaching south pole (3 marks)

A south pole moves towards a loop as shown.

A bar magnet with its south pole facing a conducting loop moves towards the loop, and the induced current in the loop is shown at the top and bottom of the edge-on viewNSmoving towards the loopcurrent out of pagecurrent into pageloop (edge-on)
Magnet and loop for the question.
  1. State the direction of the induced current as seen from the magnet side. (1 mark)
  2. Use Lenz’s law to explain your answer. (2 marks)

Question 4 Rod on rails (4 marks)

A rod of length 0.60 m moves at 2.5 m/s on rails in a field of 0.35 T. The circuit has total resistance 1.5 Ω.

  1. Calculate the emf. (1 mark)
  2. Calculate the current. (1 mark)
  3. Calculate the force needed to keep the speed constant. (1 mark)
  4. Calculate the power supplied by the force. (1 mark)

Question 5 Slow fall in a tube (2 marks)

A magnet falls more slowly through an aluminium tube than through a plastic tube of the same size. Explain why. (2 marks)

Question 6 Faraday’s law in words (2 marks)

State Faraday’s law of electromagnetic induction and explain what the minus sign represents. (2 marks)

Question 7 Units (2 marks)

Show that the unit Wb/s is equivalent to the volt. (2 marks)

Question 8 Loop leaving a field (2 marks)

A square loop moves out of a region of uniform field directed into the page, at constant speed.

  1. State the direction of the induced current. (1 mark)
  2. State what happens to the emf if the speed is doubled. (1 mark)

See the faraday's law test answers and mark scheme

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