A particle having charge of $10\,\mu C$ and $1\,\mu g$ mass moves along circular path of $10\, cm$ radius in the effect of uniform magnetic field of $0.1\, T$. When charge is at point $'P'$, a uniform electric field applied in the region so charge moves tangentially with constant speed. The value of electric field is......$V/m$

Write equation of Lorentz force.

Two very long, straight, parallel wires carry steady currents $I$ and $-I$ respectively. The distance  etween the wires is $d$. At a certain instant of time, a point charge $q$ is at a point equidistant from the two wires, in the plane of the wires. Its instantaneous velocity $v$ is perpendicular to the plane of wires. The magnitude of the force due to the magnetic field acting on the charge at this instant is

If a particle of charge ${10^{ - 12}}\,coulomb$ moving along the $\hat x - $ direction with a velocity ${10^5}\,m/s$ experiences a force of ${10^{ - 10}}\,newton$ in $\hat y - $ direction due to magnetic field, then the minimum magnetic field is

${H^ + },\,H{e^ + }$ and ${O^{ + + }}$ ions having same kinetic energy pass through a region of space filled with uniform magnetic field $B$ directed perpendicular to the velocity of ions. The masses of the ions ${H^ + },\,H{e^ + }$and ${O^{ + + }}$ are respectively in the ratio $1:4:16$. As a result

Which particles will have minimum frequency of revolution when projected with the same velocity perpendicular to a magnetic field