The disc of supply energy meter is made of which material?

Energy meter: 

• The energy meter measures electrical energy in a kilowatt-hour.
• It is also known as kilowatt-hour meter or Induction type watt-hour meter.
• It is a type of ''integrating instruments.''

Components:

Driving System:

• The components of this system are two silicon steel laminated electromagnet
• Upper magnet→ Shunt magnet→ behave as potential coil
• Lower magnet→ series magnet→ behave as current coil

Moving system: 

In this system, a thin aluminum disk placed in the air gap between the two electromagnets and mounted on a vertical shaft that is free to rotate.

Registering system: 

It registers the number of rotations of the disk which is proportional to the energy consumed directly in kilowatt-hour.

Braking system: 

This system has a permanent magnet called a brake magnet. It is located near the disk so that eddy currents are induced and a braking toque to the disk.

Solution:

Disc of the energy meter is made of aluminium.