If current is not obtained from secondary coil of an ideal transformer, then the power factor of primary coil of transformer is .........

Options

A. 0
B. `1/2`
C. 1
D. infinite

Answer

A

Explanation

The mean real power in secondary coil
`lt P gt =V_(rms) I_(rms) cos delta`
but power is not obtained in secondary coil
`therefore` In 0 = `V_(rms) I_(rms) cos delta, V_(rms) ne 0 , I_(rms) ne 0`
`therefore cos delta=0`
`therefore delta=pi/2` and power remain same in an ideal transformer .
`therefore cos delta=0`, which is power factor.