In an `RC` circuit while charging, the graph of `1n i` versis time is as shown by the dotted line in the diagram figure. Where `i` is the current. When the value of the resistance is doubled, which of the solid curve best represents the variation of `1n i` versus time

Options

A. P
B. Q
C. R
D. S

Answer

B

Explanation

`q= CE(1-e^(-t//RC))`
`I = (dq)/(dt) = E/R e^(-t//RC)`
`1n I = 1n(E)/R = t/(RC)`
`1n I V//s t` will be straight line with -ve slope and positive intercept
`Slope = -(1)/(RC)`, intercept = `1n(E/R)`
When resistance is doubled, intercept decrease and slope increase.