A coil of insulated copper wire is connected to a galvanometer. What will happen if a bar magnet is (i) pushed into the coil, (ii) withdrawn from inside the coil, (iii) held stationary inside the coil?

 

Answer

bar-magnet-pushed-inside-a-coil-of-copper gif

Galvanometer is a device which is used to check the presence of current in a circuit.

 

Since there is no battery connected in the circuit, the current that will be generated in the insulated copper wire is going to be induced current.

 

Current is induced when

  • Moving conducting Wire inside a Fixed Magnetic Field 
  • Keeping Conductor Fixed and Changing Magnetic Field

 

As bar magnet is

 

(i) pushed into the coil

The magnetic field around the coil would change.

Hence, some current will be induced in the coil.

Therefore, galvanometer will show some deflection.

 

(ii) withdrawn from inside the coil

The magnetic field around the coil would change.

Hence, some current will be induced in the coil.

Therefore, galvanometer will show some deflection, but in the opposite direction as that of Case (i).

 

(iii) held stationary inside the coil

 

Since the bar magnet is held stationary

The magnetic field around the coil remains constant.

Thus, the magnetic field does not change.

 

Hence, no current will be induced in the coil.

Therefore, galvanometer will show no deflection.

  1. Class 10
  2. Chapter 13 Class 10 - Magnetic Effects of Electric Current

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Davneet Singh
Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 9 years. He provides courses for Maths and Science at Teachoo.