$A$ satellite is revolving very close to a planet of density $\rho$. The period of revolution of the satellite is

The major product of the following reaction is

In a compound microscope,the focal lengths of the two lenses are $1.5 \, cm$ and $6.25 \, cm$. If an object is placed at $2 \, cm$ from the objective lens and the final image is formed at $25 \, cm$ from the eye lens,the distance between the two lenses is ...... $cm$.

The expression $\tan 9^{\circ}-\tan 27^{\circ}-\tan 63^{\circ}+\tan 81^{\circ}$ is equal to

The White Revolution is associated with which industry?

Two spherical conductors $A$ and $B$ of radii $1 \ mm$ and $2 \ mm$ are separated by a distance of $5 \ cm$ and are uniformly charged. If the spheres are connected by a conducting wire,then in the equilibrium condition,the ratio of the magnitude of the electric fields at the surfaces of spheres $A$ and $B$ is-