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

$A$ charged particle of charge '$q$' is accelerated by a potential difference '$V$' and enters a region of uniform magnetic field '$B$' at right angles to the direction of the field. The charged particle completes a semicircle of radius '$r$' inside the magnetic field. The mass of the charged particle is

When a positively charged particle enters a uniform magnetic field with uniform velocity, its trajectory can be:
$(1)$ a straight line
$(2)$ a circle
$(3)$ a helix

An electron is travelling along the $x$-direction. It encounters a magnetic field in the $y$-direction. Its subsequent motion will be

Statement-$1$: The path of a charged particle may be a straight line in a uniform magnetic field.
Statement-$2$: The path of a charged particle is decided by the angle between its velocity and the magnetic field acting on it.

Two ions having masses in the ratio $1: 1$ and charges $1: 2$ are projected into a uniform magnetic field perpendicular to the field with speeds in the ratio $2: 3$. The ratio of the radii of circular paths along which the two particles move is :