Question

These questions are about the relationship between AC current power supply and Inductance.

Primary Coil (magnetic field connected to source) Secondary Coil (magnetic field induced by the primary)

1. How does changing the frequency (length & height) of an AC power supply affect induced current on a secondary coil and why?

2. How does changing the distance between the primary and secondary coil affect induced current on the secondary coil and why?

3. How does reducing the number of loops (N) affect the induced current on the secondary coil and why?

4. How does an increase or decrease in the area of the loop affect induced current on the secondary coil and why?

5. How does more loops on the primary coil affect the magnitude of induced current? What is the relationship with Faraday's Law?

Answer 1

Answer of 1:

The voltage or current in AC circuit is given in sinusoidal form so it also changes the induced voltage and current because induced voltage is proportional to changing magnetic flux generated by current in primary coil.

Current in primary coil
Current amplitude in primary coil
Angular frequency in primary coil and secondary coil
Time
Magnetic flux
Magnetic field
Area of coil
Induced voltage in secondary coil
Angle between A and B

The current is given in primary coil is:

And the induced voltage is given in secondary coil is:

Therefore, from the above equation it can be seen that changing the angular frequency in primary coil affects the induced current and voltage.

Answer of 2:

Changing the distance between coils changes induced voltage and current in the secondary coil. If the distance between coils are increased, then the changing magnetic flux is not enough linked to secondary coil and for this reason smaller induced current and voltage are generated. So, keeping close to both coils give desired induced current and voltage in the secondary coil.

Answer of 3:

Magnetic flux is directly proportional to magnetic field and magnetic field is directly proportional to current in primary coil, and therefore magnetic flux generated in the primary coil is directly proportional to number of turns of coil. Therefore, if the current is changed, the changing magnetic flux is changed and for this reason the induced current and voltage are changed accordingly in the secondary coil.

Answer of 4:

Magnetic flux is given by

As explained in the previous answer, magnetic flux generated by the primary coil current is directly proportional to the area of the coil. If the area is reduced the changing magnetic flux is generated in smaller number and therefore, linkage magnetic flux to secondary coil is smaller which is responsible to the first induced voltage and then induced current in the secondary coil. Similarly, if the area of primary coil is decreases, the induced voltage and current are also decreased.

Answer of 5:

The current in the secondary coil is given by:

Where,
Number of turns in the primary coil
Mutual inductance between coil
Magnetic flux generated by primary coil

From the above equation, we can see the number of turns in the primary coil is directly proportional to induced current in the secondary coil. Therefore, if number of turns of the primary coil is increased, the induced current is increased as well. And if number of turns of the primary coil is decreased, the induced current is decreased as well.