Write speed of cathode rays. 

The colour of the positive column in a gas discharge tube depends on

An electron of charge $‘e’$ coulomb passes through a potential difference of $V$ volts. Its energy in ‘joules’ will be

Write information about negative electric charge emitted from metals when $UV$ light is incident on them or metals are heated. 

What is specific charge ? Write its standard value.

Which of the following have highest specific charge