Question

What is the effect of frequency on the torque of a moving system?

(a) torque is half of the frequency

(b) torque is twice the frequency

(c) torque is thrice the frequency

(d) torque is four times the frequency

I got this question in an international level competition.

My enquiry is from Errors in Dynamometer Wattmeter topic in division Measurement of Power and Related Parameters of Electrical Measurements

Answer 1

Right option is (b) torque is twice the frequency

The best explanation: In a wattmeter, the torque of the moving system is affected by the frequency. Torque is twice the natural frequency with respect to the supply voltage. As a result of this, pointer in the measurement scale vibrates causing difficulty in reading.