What is value (magnitude) of electric field required for field emission ?
Explain emission of electron from metal. Define work function. Write its unit, work function of metal depend on which factors ?
The ratio of momenta of an electron and an $\alpha - $particle which are accelerated from rest by a potential difference of $100 V$ is
Which one of the following devices makes use of the electrons to strike certain substances to produce fluorescence
A charge of magnitude $3e$ and mass $2m$ is moving in an electric field $\overrightarrow E .$ The acceleration imparted to the charge is
In a parabola spectrograph, the velocities of four positive ions $P,Q,R$ and $S$ are $v_1$, $v_2$, $v_3$ and $v_4$ respectively