In the Millikan's experiment, the distance between two horizontal plates is $2.5 \,\,cm$ and the potential difference applied is $250\,\, V$ . The electric field between the plates will be ....... $V/m$

In an electron gun the control grid is given a negative potential relative to cathode in order to

An electron (charge =$1.6 \times {10^{ - 19}}C$) is accelerated through a potential of $ 100,000 V$. The energy acquired by the electron is

An electron gun with its collector at a potential of $100\; V$ fires out electrons in a spherical bulb containing hydrogen gas at low pressure $(\sim 10^{-2} \;mm$ of $Hg$ . A magnetic field of $2.83 \times 10^{-4}\; T$ curves the path of the electrons in a circular orbit of radius $12.0 \;cm .$ (The path can be viewed because the gas tons in the path focus the beam by attracting electrons, and emitting light by electron capture; this method is known as the 'fine beam tube' method.) Determine $e / m$ from the data.

While doing his experiment, Millikan one day observed the following charges on a single drop

$(i)$ $6.563 \times {10^{ - 19}}C$       $  (ii)$ $8.204 \times {10^{ - 19}}C$

$(iii)$ $11.50 \times {10^{ - 19}}C$       $ (iv)$ $13.13 \times {10^{ - 19}}C$

$(v)$ $16.48 \times {10^{ - 19}}C$       $ (vi)$ $18.09 \times {10^{ - 19}}C$

From this data the value of the elementary charge $(e)$ was found to be

Which of the following law is used in the Millikan's method for the determination of charge