Question

The instrument that does not have any restoring torque is

• A. Moving iron instrument
• B. Flux meter
• C. Ballistic galvanometer
• D. D’arsonval Galvanometer

Hint:

Restoring torque is absent in moving iron instruments; their response relies on magnetic interaction.

Answer 1

The Correct Option is A

Moving iron instruments do not rely on a restoring torque provided by springs. Instead, the deflection occurs due to the attraction or repulsion of a soft iron piece in a magnetic field, and the deflection is opposed by the mechanical stiffness of the system.