Question

In an induction type energy meter, everything else remaining same, if the radial distance of the brake magnet poles form the spindle is decreased by 10%, the rotational speed of the disc will approximately

1. Increase by 23.5%
2. Decrease by 10.6%
3. Decrease by 19.4%
4. Increase by 11%

Answer 1

In an induction type energy meter, if the radial distance of the brake magnet poles from the spindle is decreased by 10%, the rotational speed of the disc will increase by 11%.The correct option is option d.

Step-by-step explanation:

For an induction type energy meter, if the radial distance of the brake magnet poles from the spindle is decreased by 10%, the rotational speed of the disc will increase by 11%.

This can be explained using the principle of conservation of angular momentum. When the radial distance is decreased, the moment of inertia of the disc decreases. As a result, the angular velocity increases to maintain the same angular momentum.

Therefore, option 4 is correct - the rotational speed of the disc will increase by 11%.