A small ball of paper has mass `9xx10^(-5) kg` and carries a charge of `5muC`. When it is held over another charged ball of paper at a distance of 2cm above it, the two balls stay in equilibrium. What is the charge on the second hall ?

A pith ball of mass 9 xx 10^(-5) kg carries a charge of 5muC . What must be charge in another pith ball placed directly 2 cm above the given pith ball such that they held in equilibrium?

A pith ball of mass 9 xx 10^(-5) kg carries a charge of 5muC . What must be charge in another pith ball placed directly 2 cm above the given pith ball such that they held in equilibrium?

A pith-ball A of mass 9xx10^(-5) kg carries a charge of 5 mu C. What must be the magnitude and sign of the charge on a pith-ball B held 2 cm directly above the pith-ball A, such that the pith-ball A remains stationary ?

A pith-ball A of mass 9xx10^-5 kg carries a chargeof +5muc . What must be the magnitude and sign of the charge on a pith-ball B held 2 cm directly above the pith-ball . A such that the pith-ball. A remains stationary?

A very tiny ball of mass 20 g carries a positive charge 0.04 muC . It is held stationary in air due to electric force by a charge fixed below it at a distance of 10 cm. What should be the magnitude and nature of charge ?

One end of a 10 cm long silk thread is fixed to a large vertical surface of a charged non-conducting plate and the other end is fastened to a small ball of mass 10 g and charge of 4 xx 10^(-6) C . In equilibrium, thread makes an angle of 60^(o) with the vertical. (a) Find the tension in the string in equilibrium. (b) Suppose the ball is slightly pushed aside and released. Find the time period of the small oscillations. (Use sigma=7.5xx10^(-7) C/m^2 )

A small ball of mass 2 xx 10^(-3) kg having a charge of 1 muC is suspended by a string of length 0.8 m. Another identical ball having the same charge is kept at the point of suspension. Determine the miniumum horizontal velocity which should be imparted to the lower ball, so that it can make complete revolution.