If $x=\sqrt{a^{\sin ^{-1} t}}, y=\sqrt{a^{\cos ^{-1} t}}$, then $\frac{d y}{d x}=\ldots .$.

A stone of mass 1 kg is tied to a string 2 m long and it's rotated at constant speed of $40 \mathrm{~ms}^{-1}$ in a vertical circle. The ratio of the tension at the top and the bottom is [Take $g=10 \mathrm{~ms}^{-2}$]

2. Two coils have a mutual inductance of 0.01 H . The current in the first coil changes according to equation, $I=5 \sin 200 \pi t$. The maximum value of emf induced in the second coil is

The radius of the earth and the radius of orbit around the sun are 6371 km and $149 \times 10^6 \mathrm{~km}$ respectively. The order of magnitude of the diameter of the orbit is greater than that of earth by