An electron (mass = $9.0 \times 10^{-31} \ kg$ and charge = $1.6 \times 10^{-19} \ C$) is moving in a circular orbit in a magnetic field of $1.0 \times 10^{-4} \ Wb/m^2$. Its period of revolution is:

$A$ particle of mass $m$ and carrying a charge $q$ enters with a velocity $v$ perpendicular to a uniform magnetic field $B$. The time period of rotation of the particle:

$A$ proton of energy $8\, eV$ is moving in a circular path in a uniform magnetic field. The energy of an alpha particle moving in the same magnetic field and along the same path will be.....$eV$

$A$ positively charged particle enters a region of a uniform transverse magnetic field as shown in the figure. Find the net deviation in the path of the particle.

An infinitely long straight conductor carries a current of $5 \, A$ as shown. An electron is moving with a speed of $10^{5} \, m/s$ parallel to the conductor. The perpendicular distance between the electron and the conductor is $20 \, cm$ at an instant. Calculate the magnitude of the force experienced by the electron at that instant in $\times 10^{-20} \, N$.

$A$ beam of well-collimated cathode rays travelling with a speed of $5 \times 10^6 \, m/s$ enters a region of mutually perpendicular electric and magnetic fields and emerges undeviated from this region. If $|B| = 0.02 \, T$,the magnitude of the electric field is: