Question

The charge flowing in a conductor varies with times as `Q = at - bt^2.` Then, the current
A. decrease linealy current
B. reaches maximum and then decrease
C. falls to zero after `t = a//2b`
D. changes at a cate of `- 2b`

Answer 1

Correct Answer - a,c,d
(a) `I = (dQ)/(dt) = (d)/(dt) (at - bt^(2)) = a- 2bt`
i.e., `I` decreases with time
(c) For `I = 0,a- 2bt = 0 or t = a//2b`
(d) Rate of change of current
`(dI)/(dt) = (d)/(dt) ( a- 2bt) = -2b`