The magnetic field at the centre of a current carrying circular coil of area ' $A$ ' is ' $B$ '. The magnetic moment of the coil is ( $\mu_0=$. permeability of free space)
A parallel combination of two capacitors of capacities ' C ' and ' $\frac{\mathrm{C}}{3}$, respectively is connected across a battery of 12 volt. When both capacitors are fully charged, the charge and energy stored in them is $Q_1, Q_2$ and $E_1, E_2$ respectively. Then the ratio of $\left(E_1-E_2\right)$ to $\left(Q_1-Q_2\right)$ is
A transparent sphere of refractive index ' $\mu$ ' and radius of curvature ' $R$ ' is kept in air. A point object is placed at a distance ' d ' from the surface of the sphere so that the real image is formed at the same distance ' $d$ ' from exactly opposite side of the sphere. The distance ' $d$ ' is
The instantaneous value of current in an a.c. circuit is $I=2 \sin \left[100 \pi t+\frac{\pi}{3}\right]$ A. The current will be maximum for the first time at $\left(\sin 90^{\circ}=1\right)$