An AC voltage V = 5 cos (1000 t) V is applied to a L-R series circuit of inductance 3 mH and resistance 4`Omega` . The value of maximum current in the circuit is …….. A.

Options

A. 1
B. `5/sqrt7`
C. `5/7`
D. 0.8

Answer

A

Explanation

By comparing ,
V=5 cos (100t)V with `V=V_m cos (omegat)V`
`omega`=1000 rad/s , `V_m` = 5 V
Impedence of series connection of L-R,
`|Z|=sqrt((omegaL)^2 + R^2)`
`=sqrt((1000xx3xx10^(-3))^2+(4)^2)`
`=sqrt(9+16)`
`=sqrt25`
`= 5Omega`
`therefore I_m=V_m/"|Z|"=5/5` = 1 A