A capacitor that is initially uncharged is connected in series with a resistor and an emf source with E = 120 V and negligible internal resistance. Just after the circuit is completed, the current through the resistor is 6.7×10−5 A . The time constant for the circuit is 4.4 s .'What are the resistance of the resistor and the capacitance of the capacitor?

Resistance = 1.791 x 10^(6) Ω

Capacitance = 2.46 x 10^(-6) F

Explanation:

We are given;

EMF; E = 120V

Current; I = 6.7 × 10^(−5) A

Time constant; τ = 4.4 s

Now, just after the circuit is completed, the capacitor acts like a wire and thus we use the loop rule;

So,

E - IR = 0

Let's make the resistance R the subject.

R = E/I = 120/(6.7 × 10^(−5)) = 1.791 x 10^(6) Ω

Now formula for time constant is given as;

τ = RC

Where C is capacitance.

Thus, C = τ/R = 4.4/(1.791 x 10^(6))

C = 2.46 x 10^(-6) F