What will be the charges on silk and glass rod when they are rubbed against each other?

A spark is produced, when two stones are struck against each other. Why?

What is the resultant vectors , when two vectors are at right angles to each other ?

Two bodies A and B are moving with velocities vec(V)_(A) and vec(V)_(B) making an 'theta' with each other. Determine the relative velocity of A with respect to B. What will be the relative velocity . When two bodies are moving at right angle to each other .

A charge of 1.0 C is placed at the top of your college building and another equal charge at the top of your house. Take the separaton between the two charges to be 2.0 km. Find the force exerted by the charges on each other. How many time of your weight is this force?

when a glass rod is rubbed with silk cloth, both get charged.

Unpolarised light is incident on a plane glass surface. What should be the angle of incidence so that the reflected and refracted rays are perpendicular to each other? (Given n=1.5)

Two bodies A and B are moving with velocities vec(V)_(A) and vec(V)_(B) making an 'theta' with each other. Determine the relative velocity of A with respect to B. What will be the relative velocity . When two bodies are moving in the apposite direction.