Question

10 million electrons pass from point P to point Q in 1 microsecond. the current and its direction is?

Answer 1

n=number of electrons=10 million=10^7
t=time taken=1 micro second=10^(-6) second
$I= \frac{q}{t}= \frac{ne}{t}= \frac{10^7(1.6*10^{-19})}{10^{-6}}=1.6*10^{-6} A$
its direction is from Q to Point P

Answer 2

The intensity of current is - 1.6*10^-6 A

Direction of current will be from Point Q to Point P.

Number of electrons - 10 million = 10^7

T = 1 microsecond = 10^-6 s

Current is defined as flow of charge per unit time.

Thus, I = q/t

Q = number of electrons* charge on 1 electron

Charge on 1 electron = - 1.6*10^-19 C.

I = - 1.6*10^-19*10^7/10^-6

I = - 1.6*10^-6 C/s

I = - 1.6*10^-6 A

Since, the sign is negative, hence direction of current will be from Point Q to Point P.