A choke coil is preferred to a resistance for reducing current in an ac circuit because .

Options

A. choke is cheap
B. there is not wastage of powerr
C. choke is compact in size
D. choke is a good absorber of heat

Answer

C

Explanation

In an AC circuit, the coil of high inductance and negligible resistance used to control current, is called the choke coil, the power factor of such a coil is given by
`cosphi=(R)/(sqrt(R^(2)+omega^(2)L^(2)))`
`~~(R)/(omegaL)" "(as" "R lt lt omegaL)`
As `R lt lt omegaL,cosphi` si very small. thus, the power absorbed by the coil is very small. the only loss of energy is due to hysteresis in the iron core, which is much less the loss of energy in the resistance that can also reduce the current if placed instead of the choke coil.