$A$ metal plate gets heated when cathode rays strike against it due to:

$A$ cathode emits $1.8 \times 10^{14}$ electrons per second when heated. When $400 \ V$ is applied to the anode,all the emitted electrons reach the anode. The charge on an electron is $1.6 \times 10^{-19} \ C$. The maximum anode current is ............ $\mu A$.

The minimum value of electric field required to pull out electrons from a metal is approximately . . . . . . $V$/cm.

Cathode rays are produced when the pressure is of the order of

Positive rays were discovered by

Write observations of various experiments which suggest that cathode rays are a stream of negatively charged particles.