Skip to content
MathsGenie logo
Open app

Course home

  1. A Level
  3. Physics AQA
  5. Question bank

Magnetic fields (A-level only)

EasyMediumHard
12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758596061626364656667686970717273747576777879
Question 75

An automated planetary probe is equipped with a single-turn search coil designed to measure local magnetic anomalies. As the probe descends into a geological rift, the magnetic flux Φ \Phi\,Φ linking the search coil varies over a 12 s interval as follows:

  • From t=0 st = 0\text{ s}t=0 s to t=3 st = 3\text{ s}t=3 s, the flux is constant at 8.0 Wb8.0\text{ Wb}8.0 Wb.
  • From t=3 st = 3\text{ s}t=3 s to t=8 st = 8\text{ s}t=8 s, the flux decreases linearly from 8.0 Wb8.0\text{ Wb}8.0 Wb to −4.0 Wb-4.0\text{ Wb}−4.0 Wb.
  • From t=8 st = 8\text{ s}t=8 s to t=10 st = 10\text{ s}t=10 s, the flux remains constant at −4.0 Wb-4.0\text{ Wb}−4.0 Wb.
  • From t=10 st = 10\text{ s}t=10 s to t=12 st = 12\text{ s}t=12 s, the flux increases linearly from −4.0 Wb-4.0\text{ Wb}−4.0 Wb to 8.0 Wb8.0\text{ Wb}8.0 Wb.

This variation is illustrated in the graph below:

Magnetic Flux vs Time

Determine the induced electromotive force (emf), E\mathcal{E}E, in the search coil during each of these four time intervals, paying careful attention to signs.

[4]

Magnetic fields (A-level only) Questions

  1. A Level
  2. /Physics
  3. /Magnetic fields (A-level only)