In the circuit shown, a `30 V` d.c. source gives a current `2.0 A` as recorded in the ammeter A and `30 V` a.c. source of frequency `100 Hz` gives a currentd `1.2 A`. The inductive reactance is

Options

A. 10 ohm
B. 20 ohm
C. `5 sqrt(34)` ohm
D. 40 ohm

Answer

2

Explanation

When d.c source, `R = (V)/(I) = (30)/(2) = 15 Omega`
When a.c. source, `Z = (30)/(1.2) = 25 Omega`
`X_(L) = sqrt((25)^(2) - (15)^(2)) = sqrt(625 - 225) = 20 Omega`