$A$ particle moving in a magnetic field increases its velocity,then its radius of the circle

Two particles $x$ and $y$ have equal charges and possess equal kinetic energy. They enter a uniform magnetic field and describe circular paths of radius of curvature $r_1$ and $r_2$ respectively. The ratio of their masses is

If a charged particle moves in a gravity-free space with uniform velocity,then which of the following is not possible? ($\overrightarrow{E} =$ electric field,$\overrightarrow{B} =$ magnetic field)

$A$ proton, a deuteron (nucleus of ${ }_1 H^2$) and an $\alpha$-particle with the same kinetic energy enter a region of uniform magnetic field moving at right angles to the field. The ratio of the radii of their circular paths is:

An electron is projected with uniform velocity along the axis of a current-carrying long solenoid. Which of the following is true?

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