A constant voltage of 25 V is applied to a series L-R circuit at t = 0 , by closing a switch . What is the pitential difference across the resister and the inductor at time t = 0?

Options

A. 0 V, 25 V
B. 12.5V, 1.25 V
C. 10 V, 15 V
D. 25 V, 0 V

Answer

B

Explanation

From the closed loop (1) , `12- 500i_1-i_1R=0`
Rightarrow `12= (1)/(50) (R+500)`
From the closed loop `(2) ,2-i_1 (500)-2 = 0`
`i_1= (1)/(50)`
Substitute equation (1) , wewe get ,
`12= (1)/(50) (R+500) Rightarrow 600 = R+500`
`R= 100omega`