Question

When `100 V` DC is applied across a solenoid, a current of `1.0 A` flows in it. When `100 V` AC is applied across the same coil. The current drops to `0.5A`. If the frequency of the ac source is `50 Hz`, the impedance and inductance of the solenoid are
A. 200 ohm and 0.55 Henry
B. 100 ohm and 0.86 Henry
C. 200 ohm and 1.0 Henry
D. 100 ohm and 0.93 Henry

Answer 1

Correct Answer - A

`R=100/1=100 Omega`
`Z=100/0.5 =200 Omega`
`200=sqrt(100^(2)+x_(L)^(2))`
`X_(L)=100sqrt(3)`
`L=(sqrt(3))/(pi)=0.55H`