Paper 3: Required practical 11 - Magnetic flux linkage

Question 1

What piece of apparatus can be used to measure the induced emf inside a current carrying circular coil?

Answer 1

A search coil connected to an oscilloscope

Question 2

Why must an alternating current source be used in this experiment?

Answer 2

An AC source should be used so that the magnetic flux through the search coil is constantly changing

Question 3

How can an oscilloscope be used to measure the induced emf?

Answer 3

• When connected to the search coil, the oscilloscope will show the waveform of the induced emf
• By turning the time base off, this will become a vertical line that gives the peak to peak value of the emf

Question 4

What preliminary experiment will need to be undertaken before carrying this experiment out?

Answer 4

• Needed to determine a suitable voltage and frequency for the circular coil
• The induced emf must be large enough to be easily measured using the search coil and oscilloscope

Question 5

How can the angle measurements be taken in this experiment?

Answer 5

• Circular protractor card could be positioned under the circular coil and fixed in place with an optical pin
• Allows the angle to be measured from the same position each time

Question 6

Why might an ammeter be used in the preliminary experiment?

Answer 6

Important to ensure that the current passing through the coil doesn’t exceed the manufacturer’s guidelines