The height at which the weight of a body becomes $1/16^{th}$ of its weight on the surface of the earth (radius $R$) is: (in $R$)

$A$ body projected vertically upwards crosses a point twice in its journey at a height $h$ just after $t_1$ and $t_2$ seconds. Maximum height reached by the body is

In non-cyclic photophosphorylation,the electron $(e^-)$ released by $PSI$ is accepted by.......

Copper sulphate dissolves in excess of $KCN$ to give

$A$ uniform rod of mass $M$ and length $L$ is placed on a smooth horizontal surface. $A$ horizontal force $F$ is applied at one end of the rod perpendicular to its length. The acceleration of the centre of mass of the rod is:

Acetone on addition to methyl magnesium bromide forms a complex,which on decomposition with acid gives $X$ and $Mg(OH)Br$. Which one of the following is $X$?