In $1897$, J.J.Thomson invented which particle ?
From the following, what charges can be present on oil drops in Millikan's experiment
(Here e is the electronic charge)
Which of the following is not the property of a cathode ray
What is value (magnitude) of electric field required for field emission ?
In Thomson spectrograph experiment, four positive ions $P,Q,R$ and $S$ are situated on $Y-X$ curve a shown in the figure
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.