Ratio of power factor in two A.C. circuits (i) containing only resistance and (ii) containing only inductor is …….

Options

A. 1
B. 0
C. `oo`
D. x (where x `in` N)

Answer

C

Explanation

(i)Only resistor : tan `delta_1=(X_L-X_C)/R=0` `(because X_L=X_C=0)`
`therefore delta_1=0 rArr cos delta_1=1`….(1)
(ii) Only inductor :
`tan delta_2=(X_L-X_C)/R=(X_L-0)/0 =oo (because X_C=R=0)`
`therefore delta_2=pi/2` rad
`therefore cosdelta_2=0`....(2)
From (1) and (2)
`(cosdelta_1)/(cos delta_2)=1/0 = oo`