Ari oil drop, of 12 excess electrons is held stationary under a constant electric field of `2.55x10^4N//C` in Millikan's oil drop experiment. The density of the oil is `1.26g//m^3` Estimate the radius of the drop.

If an oil drop of weight 3.2xx10^(-13) N is balanced in an electric field of intensity 5xx10^(5) V/m, find the charge on oil drop.

A proton is moving with a uniform velocity of 10^(6)m.s^(-1) along the Y-axis, under the joint action of a magnetic field along Z-axis and an electric field of magnitude 2xx10^(4)V.m^(-1) along the negative X-axis. If the electric field is switched off, the proton starts moving in a circle. The radius of the circle is nearly (given: (e)/(m) ratio for proton ~~10^(8)C.kg^(-1) )

An oil drop has 8.01xx10^-19 C charge calculate the number of electrons in this drop.

An electric dipole placed at an angle of 30^(@) with a uniform electric field of intensity 10^(4)N.C^(-1) experiences a torque of 9xx10^(-26)N.m . What is the moment of the electric dipole?

In Millikan's experiment, static electric charge on the oil drops has been obtained by shining X-rays. If the static charge on the oil drop is -1.282xx10^(-18)C , calculate the number of electrons present on it.

An oil drop of density 950 kg. m^-3 and radius 10^-6 m is falling through air. The density of air is 1.3 kg. m^-3 and its coefficient of viscosity is 181xx10^-7 SI unit. Determine the terminal velocity of the oil drop. [g=9.8m. S^-2]