In Thomson's method of determining $e/m$ of electrons
Electric and magnetic fields are parallel to electrons beam
Electric and magnetic fields are perpendicular to each other and perpendicular to electrons beam
Magnetic field is parallel to the electrons beam
Electric field is parallel to the electrons beam
A stick of $1 \,m$ is moving with velocity of $2.7 \times {10^8}m{s^{ - 1}}$. ........... $m$ is the apparent length of the stick $(c = 3 \times {10^8}m{s^{ - 1}})$
When electron beam passes through an electric field, they gain kinetic energy. If the same beam passes through magnetic field, then
The ratio of momenta of an electron and an $\alpha - $particle which are accelerated from rest by a potential difference of $100 V$ is
An $\alpha$ particle is accelerated through a p.d of ${10^6}$ volt then $ K.E$ . of particle will be .......... $MeV$
Positive rays consists of