transient response of RC and RL circuits

In figure the switch was closed for a long time before opening at t=0. The voltage Vx at t=0+ will be( Gate question)

• 25 V

• 50 V

• – 50 V

• 0 V

In the circuit shown, Vc is 0 volts at t = 0 sec. For t > 0, the capacitor current ,Ic(t) where t is in seconds, is given by

• 0.50 exp (– 25t) mA

• 0.25 exp (– 25t) mA

• 0.50 exp (–12.5t) mA

• 0.25 exp (– 6.25t) mA

The switch in the figure below was closed for a long time. It is opened at t = 0. The current in the inductor of 2 H for t ≥ 0, is

• 2.5e -4t

• 5e -4t

• 2.5e -0.25t

• 5e -0.25t

A series R-C circuit consists of resistor of 10 and capacitor of 0.1F as shown in the figure. A constant voltage of 20V is applied to the circuit at t = 0. What is the current in the circuit at t = 0?

• a) 1

• b) 2

• c) 3

• d) 4

A series R-L circuit with R = 30Ω and L = 15H has a constant voltage V = 60V applied at t = 0 as shown in the figure. Determine the current (A) in the circuit at t = 0+.

• a) 1

• b) 2

• c) 3

• d) 0