A ball of mass `10^(-2) kg` and having charge `+ 3 xx 10^(-6)C` is tied at one end of a `1m` along thread. The other end of the thread is fixed and a charge `- 3 xx 10^(-6) C` is placed at this end. The ball can move in the circulr orbit of radius `1m` in the vertical plane. Initially, the ball is at the bottom. Find the monimum initial horizontal velocity of the ball, so that it will be able to complete the full circle.

A particle of mass 6.4xx10^(-27) kg and charge 3.2xx10^(-19)C is situated in a uniform electric field of 1.6xx10^5 Vm^(-1) . The velocity of the particle at the end of 2xx10^(-2) m path when it starts from rest is :

A ball of mass 1 g having a charge of 20 mu C is tied to one end of a string of length 0.9 m can rotate in a vertically plane in a uniform electric minimum horizontal velocity that must be given to the ball at the lowest position so that is complete the verticle circle is (let g= 10 ms^(-1))

A particle of mass m and charge q is attached to a light insulating thread of length L. The other end of the thread is secured at point O. Exactly below point O, there is a small ball having charge Q fixed on an insulating horizontal surface. The particle remains in equilibrium vertically above the ball with the string taut. Distance of the ball from point O is L. Find the minimum value of Q for which the particle will be in a stable equilibrium for any gentle horizontal push given to it.

A simple pendulum consisting of a ball of mass m tied to a thread of length l is made to swing on a circular arc of angle q in a vertical plane. At the end of this arc, another ball of mass m is placed at rest. The momentum transferred to this ball at rest by the swinging ball is

A pith ball carrying a charge of 3 xx 10^(-10) C is suspended by an insulated thread of length 50 cm .When a uniform electric filed is applied in a horizontal direction , the ball is found to deflect by 2 cm from the vertical. If the mass of the ball is 0.5 gm , the intensity of the electric field is :

An alpha particle of charge 3.2 xx 10 ^(-19) C and mass 6.8 xx 10 ^(-27) Kg is initially moving at speed 10 ^(7) m/s when it is at far distance from another fixed point charge 112 xx 10 ^(-19) C . Find the distance of closest approach.

A free pith ball of mass 6g carries a positive charge of (1//3) xx 10^(-7) C . What is the nature and magnitude of charge that should be given to a second pith ball fixed 5 cm vertically below the former pith ball so that the upper pith ball is stationary.

A 1 mg ball carrying a charge of 2xx10^-8 C hangs from a thread. When a large conducting plate of charge is brought near the ball, the thread makes an angle of 30^@ with the plate. What is the surface charge density of the plate?