A narrow electron beam passes undeviated through an electric field $E = 3 \times {10^4}volt/m$ and an overlapping magnetic field $B = 2 \times {10^{ - 3}}Weber/{m^2}$. If electric field and magnetic field are mutually perpendicular. The speed of the electrons is
$60 m/s$
$10.3 \times {10^7}m/s$
$1.5 \times {10^7}m/s$
$0.67 \times {10^{ - 7}}m/s$
Which particles are responsible for conductivity of metals ?
In Millikan's experiment for the determination of the charge on the electron, the reason for using the oil is
In $1897$, J.J.Thomson invented which particle ?
A charge of magnitude $3e$ and mass $2m$ is moving in an electric field $\overrightarrow E .$ The acceleration imparted to the charge is
Cathode rays and canal rays produced in a certain discharge tube are deflected in the same direction if