1.
The energy meter works on the principle of ___________.
A
Differential
B
Combination
C
Power
D
Induction
View Answer
Correct Answer: D — Induction
Explanation:
The correct answer is D: Induction.
An energy meter operates on the principle of electromagnetic induction. It measures the amount of electrical energy consumed over a specific period (in kWh) and is essential for utility billing.
How it works:
- Voltage Coil: Connected across the load; produces a magnetic field proportional to the applied voltage.
- Current Coil: Connected in series with the load; generates a magnetic field proportional to the current through the load.
- Interaction of Magnetic Fields: The interaction between these two magnetic fields induces eddy currents in an aluminum disc, creating a torque that causes the disc to rotate.
- Disc Rotation: The rotational speed of the aluminum disc is directly proportional to power consumption — higher power means faster rotation.
- Counting Mechanism: The disc rotation drives a gear mechanism that translates rotation into a numerical display of energy consumed in kilowatt-hours (kWh).