Question

How long should a flow of ${10}^{19}$ electrons be maintained between two points A and B to have a constant current of 8 A flowing between them?

• A. $8\times {10}^{-19}$ s
• B. 5 s
• C. $1.6\times {10}^{19}$ s
• D. 0.2 s

Answer 1

The correct option is D

0.2 s

Given: Number of electrons $n={10}^{19}$, charge of each electron $=1.6\times {10}^{-19}$
Current $I=8A.$
We know that, q=ne
Also, I = $\frac{q}{t}$
Hence t = $\frac{ne}{I}$ = $\frac{{10}^{19}\times 1.6\times {10}^{-19}}{8}$ = 0.2 s