# Problem: The switch in the figure has been in position a for a long time. It is changed to position b at t=0s.a) What is the charge Q on the capacitor immediately after the switch is closed?b) What the current I through the resistor immediately after the switch is closed?c) What is the charge Q on the capacitor at t=50 × 10-6 s?d) What is the current I through the resistor at t=50 × 10-6 s?e) What is the charge Q on the capacitor at t=200 × 10-6 s?f) What is the current I through the resistor at t=200 × 10-6 s?

###### FREE Expert Solution

The charge stored in a capacitor:

$\overline{){\mathbf{Q}}{\mathbf{=}}{\mathbf{C}}{\mathbf{V}}}$

Ohm's law:

$\overline{){\mathbf{V}}{\mathbf{=}}{\mathbf{I}}{\mathbf{R}}}$

Charge in capacitor after sometime:

$\overline{){\mathbf{Q}}{\mathbf{=}}{{\mathbf{Q}}}_{{\mathbf{0}}}{{\mathbf{e}}}^{\mathbf{\left(}\mathbf{-}\mathbf{t}\mathbf{/}\mathbf{R}\mathbf{C}\mathbf{\right)}}}$

(a)
Q = CV = 4 × 10-6 × 9 = 36 × 10-6 C
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###### Problem Details
The switch in the figure has been in position a for a long time. It is changed to position b at t=0s.

a) What is the charge Q on the capacitor immediately after the switch is closed?

b) What the current I through the resistor immediately after the switch is closed?

c) What is the charge Q on the capacitor at t=50 × 10-6 s?

d) What is the current I through the resistor at t=50 × 10-6 s?

e) What is the charge Q on the capacitor at t=200 × 10-6 s?

f) What is the current I through the resistor at t=200 × 10-6 s?