Cathode rays are produced when the pressure is of the order of
$2 cm$ of $Hg$
$0.1 cm$ of $Hg$
$0.01 mm$ of $Hg$
$1$ $\mu m$ of $Hg$
What is value (magnitude) of electric field required for field emission ?
What is the unit of energy in atomic and nuclear physics ? Define it.
In a Millikan's oil drop experiment the charge on an oil drop is calculated to be $6.35 \times {10^{ - 19}}C$. The number of excess electrons on the drop is
Which of the following is not the property of a cathode ray
A beam of cathode rays is subjected to crossed electric $(E)$ and magnetic fields $(B).$ The fields are adjusted such that the beam is not deflected. The specific charge of the cathode rays is given by (where $V$ potential diffrence between kethod and anode)