Which of the following compounds does not exhibit mutarotation?

$A$ radioactive nucleus $A$ with a half-life $T$ decays into a nucleus $B$. At $t = 0$,there is no nucleus $B$. At some time $t$,the ratio of the number of $B$ to that of $A$ is $0.3$. Then,$t$ is given by:

The depletion layer in the $p-n$ junction is caused by

The masses of neutron,proton and deuteron in amu are $1.00893$,$1.00813$ and $2.01473$,respectively. The packing fraction of the deuteron in amu is

During the reaction of permanganate with thiosulphate,the change in oxidation state of manganese occurs by a value of $3$. Identify which of the below media will favour the reaction.

$A$ particle of mass $10\, g$ is kept on the surface of a uniform sphere of mass $100\, kg$ and a radius of $10\, cm$. Find the work to be done against the gravitational force between them to take the particle far away from the sphere. (Take $G = 6.67 \times 10^{-11} \, Nm^2/kg^2$)