A spherical oil drop, radius `10^(-4)` cm has on it at a certain a total charge of 40 electrons. Calculate the energy that would be required to place an additional electron on the drop.

A spherical oil drop of raiuds 10^-4 cm has on it at a certain time a charge of 40 electrons. Calculate the energy that would be required to place an additional electron on the drop. Charge on a electron =1.6 xx 10^-19 C

In Millikan's experiment, an oil drop of radius 10^(-4) cm remains suspended between the plates which are 1 cm apart. If the drop has charge of 5e over it, calculate the potential difference between the plates. The density of oil may be taken as 1.5 gcm^(-3) .

An object with an initial charge of 4 C is given 9 xx 10^19 additional electrons, Calculate the net charge on the object.

An oil drop of radius 0.10mm spreads on a circular film of diameter 20 cm. Calculate the molecules size of the oil drop on the film.

An electron in a hydrogen -like atom is in an excited state. It has a total energy of -3.4 eV. Calculate the kinetic energy of the electron.

A spherical shell of radius 20 cm has 20 mu C charge placed in vacuum. Calculate the electric field intensity (i) at a distance of 15 cm and (ii) at a distance of 40 cm from the centre of the spherical shell.

An oil drop of radius 10^(-6)m carries a charge equal to that on an electron. If the density of the oil is 2xx10^(3)kg m^(3) , find the electric field required to keep it stationary. Take e=1.6xx10^(-19)C and g=9.8 ms^(-2) .