Assertion: An $\alpha -$particle and a deuteron having the same kinetic energy enter in uniform magnetic field perpendicular to the field. Then the radius of the circular path of $\alpha$-particle will be more.

Reason: $\frac{q}{m}$ ratio of an $\alpha -$particle is more than the $\frac{q}{m}$ ratio of a deuteron.

Assertion: A charged particle is rotating in a circular path in uniform magnetic field. Then, plane of circle is perpendicular to the magnetic field.

Reason: Circular motion is a two-dimensional motion.

Assertion: At the centre of a circular current carrying loop $I_1$, there is an infinitely long straight current carrying wire $I_2$ perpendicular to the plane of the circle. Then, magnetic force of attraction between two is zero.

Reason: Magnetic field of $I_1$ at centre is inwards, parallel to $I_2$.

Assertion: If the velocity of charged particle in a uniform magnetic field at some instant is, $\left(a_1\hat{\mathrm{i}}-a_2\hat{\mathrm{j}}\right)$ and at some other instant is $\left(b_1\hat{\mathrm{i}}+b_2\hat{\mathrm{j}}\right)$, then $a_1^2+a_2^2=b_1^2+b_2^2$.

Reason: Magnetic force cannot change velocity of a charged particle.