question_answer

In the circuit shown in figure, the switch is shifted from position 1 to 2 at t = 0. The switch was initially in position 1 since a long time. The graph between charge on upper plate of capacitor versus time -

A)        

B)

C)         

D)

Correct Answer: D

Solution :

[d] \[q=2C\varepsilon -\left[ 2C\varepsilon -\left( -C\varepsilon  \right) \right]{{e}^{\frac{t}{2RC}}}\] \[=2C\varepsilon -3C\varepsilon {{e}^{\frac{t}{2RC}}}\] initial charge \[=-C\varepsilon \] final charge \[=2C\varepsilon \]