Question

The charge flowing in a conductor varies with time as `Q ="at"- (1)/(2)bt^(2)+(1)/(6)ct^(3)`, where a,b,c are positive constant. Then, the current `i = (dQ)/(dt)`
A. has an initial value a
B. reaches a minimum value after time `b//c`
C. reaches a maximum value after time `b//c`
D. has a minimum value

Answer 1

Correct Answer - A::B::D
`i = a-bt+(1)/(2)ct^(2)`
(A) at `t = 0" "i = a`
`(B) (di)/(dt) =- b+ct=0" "thereforet=(b)/(c )`
`(d^(2)i)/(dt^(2))=cgt0" "therefore"minima"`