The magnetic force acting on a charged particle of charge $-2\, \mu C$ in a magnetic field of $2\, T$ acting in the $y$-direction,when the particle velocity is $(2\hat{i} + 3\hat{j}) \times 10^6\, m/s$,is:

$A$ magnetic field:

$A$ charged particle enters a uniform magnetic field perpendicular to its velocity. The magnetic field:

$A$ proton (mass $m$ and charge $+e$) and an $\alpha$-particle (mass $4m$ and charge $+2e$) are projected with the same kinetic energy at right angles to a uniform magnetic field. Which one of the following statements will be true?

$A$ particle having a charge of $10.0\,\mu C$ and mass $1\,\mu g$ moves in a circle of radius $10\,cm$ under the influence of a magnetic field of induction $0.1\,T$. When the particle is at a point $P$, a uniform electric field is switched on so that the particle starts moving along the tangent with a uniform velocity. The electric field is......$V/m$

$A$ rectangular region $ABCD$ contains a uniform magnetic field $B_0$ directed perpendicular to the plane of the rectangle. $A$ narrow stream of charged particles moving perpendicularly to the side $AB$ enters this region and is ejected through the adjacent side $BC$ suffering a deflection through $30^{\circ}$. In order to increase this deflection to $60^{\circ}$,the magnetic field has to be