Question

A capacitor stores energy of 1.25 J. If when it is connected by means of a switch to a 15-Ω resistor it discharges to half this value in 15 s. What is the initial voltage across the capacitor?
Given That
U: is the capacitor's energy
C: is the capacitance
R: is the resistance
q: is the capacitor's charge

Answer 1

@Esraa are you here?

Answer 2

Yes

Answer 3

@ash2326

Answer 4

We are give initial energy as 1.25 J so we have
\[\frac{1}{2} CV^2=1.25 \text{Joules}\]
Do you agree with this?

Answer 5

Yeah

Answer 6

You know how a capacitor charged at a potential V, discharges through a resistor?

Answer 7

No

Answer 8

OK, Let's discuss this. It'll take sometime and I need one favor from you!!!

Answer 9

Sure, but plz can u summarize it I have a time limit

Answer 10

Ok, I'll try to do i ASAP
Suppose I have a capacitor C farad with initial voltage V and it's connected with a resistor R. Capacitor will discharge through the resistor but it won't discharge instantly. It'll take some time.
Do you agree with this?

Answer 11

Yes

Answer 12

Let the voltage at any time t be V(t) note that just V is the initial voltage,
Now the current flowing through the circuit at any time be I
Now tell me what's the current through the capacitor ?