Electromagnetic inductionEdexcel A-Level Physics: Mind map

Exam questions on Electromagnetic induction

1. A bar magnet is pushed, north pole first, into one end of a long solenoid that is connected to a sensitive centre-zero voltmeter.
   Explain, using the principle of conservation of energy, why the induced current must produce a magnetic field that opposes the movement of the magnet.2 marks
2. A flat coil of 400 turns and cross-sectional area 2.5 × 10⁻³ m² is placed with its plane perpendicular to a uniform magnetic field. The flux density falls uniformly from 0.80 T to 0.20 T in 0.30 s.
   The same fall in flux density, from 0.80 T to 0.20 T, now takes 0.60 s instead of 0.30 s. Calculate the new average induced e.m.f. and explain your answer.2 marks
3. A flat rectangular coil of 50 turns and area 6.0 × 10⁻³ m² is held with its plane perpendicular to a uniform magnetic field of flux density 0.40 T. It is rotated through 90° about an axis lying in its plane, in a time of 0.050 s, so that its plane finishes parallel to the field lines.
   Calculate the initial flux linkage of the coil and the average e.m.f. induced in it during the rotation.3 marks