In Millikan's oil drop experiment for the determination of the charge on the electron,the reason for using oil is:

An isolated solid metallic sphere is given $ + Q$ charge. The charge will be distributed on the sphere:

What is quantization of charge? What is the reason for quantization?

Consider a neutral conducting sphere. $A$ positive point charge is placed outside the sphere. The net charge on the sphere is then,

What is the order of current flowing during lightning in the sky?

Assertion $(A)$: Electromagnetic force is enormously strong as compared to gravitational force. Yet,gravity dominates in large-scale phenomena (e.g.,formation of galaxies).
Reason $(R)$: Existence of positive and negative charges makes matter mostly electrically neutral.
Which of the following is true?