In Milikan’s experiment, static electric charge on the oil drops has been obtained by shining X-rays. If the static electric charge on the oil drop is -1.282 × 10-18C, calculate the number of electrons present on it.

In Milikan’s experiment, static electric charge on the oil drops has been obtained by shining X-rays. If the static electric charge on the oil drop is -1.282 × 10^-18C, calculate the number of electrons present on it.
Answer
Charge on the oil drop = 1.282 ×10^-18C
Charge on one electron = 1.6022 × 10^-19C
∴Number of electrons present on the oil drop