Question

A circuit consisting of a 140 µF capacitor in series with a 2 MΩ resistor is connected across a 6 V battery. What is the time constant of the circuit? Answer in units of s.

Answer 1

The time constant of an RC circuit is given by the product between the resistance and the capacitance of the circuit:

`\tau = RC`
where R is the resistance and C the capacitance.

For the circuit in our problem,

`R=2M\Omega = 2 \cdot 10^6 \Omega`
and

`C=140 \mu F = 140 \cdot 10^(-6)F`

Therefore, the time constant of this circuit is

`\tau =RC=(2 \cdot 10^(6) \Omega)(140 \cdot 10^(-6) F)=280 s`