Which polymer is used as a lubricant and an electrical insulator?

The diameter of an oxygen molecule is $2.94 \times 10^{-10} \ m$. The Van der Waals gas constant '$b$' in $m^3/mol$ will be:

The four distinct points $(0,0), (2,0), (0,-2)$ and $(k,-2)$ are concyclic,if $k$ is equal to

Two bodies have their moments of inertia $I$ and $2I$ respectively about their axes of rotation. If their kinetic energies of rotation are equal,their angular momenta will be in the ratio:

Earthworms are ........

The Lanthanoid contraction is responsible for the fact that