1)

In the circuit shown here, the point C is kept connected to point A till the current flowing through the circuit becomes constant. Afterwards, suddenly point C is disconnected from point A and connected to point B at time t=0, Ration of the voltage  across resistance and the inductor at t=L/R will be equal to 

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A) $\frac{e}{1-e}$

B) 1

C) -1

D) $\frac{1-e}{e}$

Answer:

Option C

Explanation:

 After connecting  C to B hanging the switch, the circuit will act like an L-R discharging circuit.

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Applying Kirchhoff's loop  equation,

  $V_{R}+V_{L}=0\Rightarrow V_{R}=-V_{L}$

$\frac{V_{R}}{V_{L}}=-1$