An ideal transformer is connected to a 250 V AC mains and its output voltage is 25 V . This transformer is then used to light a bulb with ratings 60 W , 25 V. Calculate the current in the primary coil of the circuit.

Options

A. Input voltage cannot be AC voltage, but a DC voltage
B. Maximum input voltage is 220 V
C. The meter reads not V but`lt V^(2)gt` and is calibrated to read `sqrt(lt V^(2) gt)`
D. The pointer of the meter is stuck by some mechanical defect

Answer

C

Explanation

The voltmeter connected to AC mains reads mean value `(lt V^(2) gt )` and is calibrated in such a way that it gives value of `sqrt(lt V^(2) gt)` , which is multiplied by form factor to give rms value