`10^(12)alpha`- particles (Nuclei of helium) per second falls on a neutral sphere, calculate time in which sphere gets charged by `2mu C`.

A spherical capacitor has an inner sphere of radius 10 cm and outer sphere of radius 12 cm . The outer sphere is earthed and the inner sphere is given a charge of 5 mu C . Find its capacitance.

A spherical capacitor has an inner sphere of radius 10 cm and outer sphere of radius 12 cm . The outer sphere is earthed and the inner sphere is given a charge of 5 mu C . The capacitance of the capacitor is

There is a fixed sphere of radius R having positive charge Q uniformly spread in its volume. A small particle having mass m and negative charge (– q) moves with speed V when it is far away from the sphere. The impact parameter (i.e., distance between the centre of the sphere and line of initial velocity of the particle) is b. As the particle passes by the sphere, its path gets deflected due to electrostatics interaction with the sphere. (a) Assuming that the charge on the particle does not cause any effect on distribution of charge on the sphere, calculate the minimum impact parameter b0 that allows the particle to miss the sphere. Write the value of b_(0) in term of R for the case 1/2mV^(2)=100.((kQq)/(R)) (b) Now assume that the positively charged sphere moves with speed V through a space which is filled with small particles of mass m and charge – q. The small particles are at rest and their number density is n [i.e., number of particles per unit volume of space is n]. The particles hit the sphere and stick to it. Calculate the rate at which the sphere starts losing its positive charge (dQ)/(dt). Express your answer in terms of b_(0)

An alpha particle (_2He^4) is moving directly towards a stationary gold nucleus (_(79)Au^(197)) .The alpha -particle and the gold nucleus may be considered to be solid spheres with the charge and mass concentrated at the centre of each sphere.When the two spheres are just toching,the sepaation of their centres is 9.6 xx 10^(-15) m . the alpha particle and the gold nucleus may be assumed to be an isolatedd system.Calculate for the alpha particle just in contact with the gold nucleus, its electric potential energy.

A solid metal sphere of radius r has charge +Q. The sphere has radius 36 cm This charge is one the surface of the sphere but it may be considered to be a point charge at its centre. A spark suddenly connects the metal sphere in to the earth, causing the potnetial of the sphere to be reduced from 7.0 xx 10^5V to 2.5 xx 10^5V . Calculate the energy dissipated in the spark.

Three metallic spheres A, B and C having radii are in ratio 1 : 2 : 3 . Charge on sphere A is 6 mu C and sphere B and C are electrically neutral. If sphere A first contact with sphere B and then from C and ultimately contact from sphere B, then now charge on spheres A, B and C respectively will be-

An electric flux of 6.5 xx 10 ^ 3 N * m ^ 2 * C ^ ( - 1 ) is linked with a sphere due to some charge placed in vaccum inside the sphere. Calculate the magnitude of the charge.