An oxide coated filament is useful in vacuum tubes because essentially
It has high melting point
It can withstand high temperatures
It has good machanical strength
It can emit electrons at relatively lower temperatures
Which of the following is not the property of a cathode ray
An electron of charge $‘e’$ coulomb passes through a potential difference of $V$ volts. Its energy in ‘joules’ will be
In Milikan’s experiment, an oil drop having charge $q$ gets stationary on applying a potential difference $V$ in between two plates separated by a distance $‘d’$. The weight of the drop is
Define work function of metal and write its unit.
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