Question

An oil drop has $6.39\times {10}^{-19}C$ charge. What will be the number of electrons in this drop?

• A. 2
• B. 4
• C. 8
• D. 16

Answer 1

The correct option is B 4

The charge on one electron is $1.60\times {10}^{-19}C$.

From the formula $q=n\times e$,

The number of electrons $n=\frac{6.39\times {10}^{-19}}{1.60\times {10}^{-19}}=4$.

Hence, the number of electrons in the drop is 4.