Assertion: A beam of electron can pass undeflected through a region of $E$ to $B$.

Reason: Force on moving charged particle due to magnetic field may be zero in some cases.

Assertion: If the path of a charged particle in a region of uniform electric and magnetic field is not a circle, then its kinetic energy may remain constant.

Reason: In a combined electric and magnetic field region, a moving charge experiences a net force $F=q\overrightarrow{E}+q\left(\overrightarrow{v}\times \overrightarrow{B}\right)$, where symbols have their usual meanings.

Assertion: Flux of magnetic field $B$ through a closed surface is equal to zero.

Reason: Magnetic field lines are closed curves. They do not have a beginning or an end.

Assertion: A flexible wire loop of irregular shape carrying current when placed in a uniform external magnetic field acquires a circular shape.

Reason: For a given perimeter circular shape is having the greatest area.

Assertion: If a charged particle is projected in a region where, $B$ is perpendicular to the velocity of projection, then the net force acting on the particle is independent of its mass.

Reason: The particle is performing uniform circular motion and force acting on it is, $\frac{m{v}^2}{r}$.

Assertion: In non-uniform magnetic field speed of a charged particle varies.

Reason: Work done by magnetic force on a charged particle is always zero.

Assertion: Three infinitely long current carrying wires have equal currents and they are equally spaced. The magnitude of magnetic force on all three is same.

Reason: Net force on wire-$2$ is zero.

Assertion: Two infinitely long wires $A$ and $B$ carry unequal currents both in an inward direction. Then, there is only one point (excluding the points at infinity) where the net magnetic field is zero.

Reason: That point lies between points $A$ and $B$.

Assertion: Path of a charged particle in uniform magnetic field cannot be a parabola if no other forces (other than magnetic force) are acting on the particle.

Reason: For parabolic path a constant acceleration is required.