Assertion: Magnetism is relativistic.

Reason: When we move along with the charge, so that there is no motion relative to us, we find no magnetic field associated with the charge.

Assertion: Steel is not attracted by a magnet

Reason: Steel is not a magnetic substance.

Assertion: When the radius of a circular wire carrying current is doubled, its magnetic moment becomes four times.

Reason: Magnetic moment is directly proportional to the area of the loop.

Assertion: It is not necessary that every magnet has one North pole and one South pole.

Reason: It is a basic fact that magnetic poles occur in pairs.

Assertion: Relative magnetic permeability has no units and no dimensions.

Reason: ${\mu }_{\mathrm{r}}=\frac{\mu }{{\mu }_0}$, where the symbols have their standard meaning.

Assertion: The net magnetic flux coming out of a closed surface is always zero.

Reason: Unlike poles of equal strength exist together.

Assertion: A magnet suspended freely in a uniform magnetic field experiences no net force, but a torque that tends to align the magnet along the field.

Reason: Net force $mB-mB=0$. But the forces on North and South poles being equal, unlike and parallel make up a couple that tends to align the magnet, along the field.

Assertion: If one arm of a U-tube containing a diamagnetic solution is placed in between the poles of a strong magnet with the level in line with the field, the level of the solution falls.

Reason: Diamagnetic substances are repelled by the magnetic field.