Q.

The charge flowing in a conductor changes with time as Q(t)=αt-βt2+γt3, where α, β and γ are constants. Minimum value of current is            [2023]

1 α-3β2γ  
2 α-γ23β  
3 β-α23γ  
4 α-β23γ  

Ans.

(4)

Q=(αt-βt2+γt3)

i=dQdt=(α-2βt+3γt2)

didt=(3γt-2β)=0t=β3γ

i=(α-2βt+3γt2)=(α-β23γ)