Which is the major product of the following reaction?

For $|x| < 1$,the constant term in the expansion of $\frac{1}{(x-1)^2(x-2)}$ is

Which of the following has the highest electrode potential?

Statement $1$: If the points $(1,2,2), (2,1,2), (2,2,z)$ and $(1,1,1)$ are coplanar,then $z=2$.
Statement $2$: If the $4$ points $P, Q, R$ and $S$ are coplanar,then the volume of the tetrahedron $PQRS$ is $0$.

$A$ body of mass $m$ hangs at one end of a string of length $l$,the other end of which is fixed. It is given a horizontal velocity so that the string just reaches a position where it makes an angle of $60^o$ with the vertical. The tension in the string at the mean position is:

The wavelengths of electron waves in two orbits is $3: 5$. The ratio of kinetic energy of electrons will be