A circular coil of wire consisting of 100 turns each of radius 9 cm carries a current of 0.4 A . The magnitude of the magnetic field at the centre of coil is $\left[\mu_0=12.56 \times 10^{-7} \mathrm{SI}\right.$ Unit]

A simple harmonic progressive wave is represented as $y=0.03 \sin \pi(2 t-0.01 x) \mathrm{m}$. At a given instant of time, the phase difference between two particles 25 m apart is

The equation of state for 2 g of oxygen at a pressure ' $P$ ' and temperature ' $T$, when occupying a volume ' $V$ ' will be

The magnetic dipole moment of a short magnetic dipole at a distant point along the equator of magnet has a magnitude of ' $X$ ' in SI units. If the distance between the point and the magnet is halved then the magnitude of dipole moment will be