Which of the following is related to genetic engineering?

$CH_4$ diffuses two times faster than a gas $X$. The number of molecules present in $32 \ g$ of gas $X$ is ($N$ is Avogadro number).

Which has the maximum number of molecules among the following?

$A$ body is projected vertically from the surface of the earth of radius $R$ with a velocity equal to half of the escape velocity. The maximum height reached by the body is

In the following diagram,the charge and potential difference across $8\, \mu F$ capacitance will be nearly

Three rods $A, B,$ and $C$ of thermal conductivities $K, 2K,$ and $4K$ and equal cross-sectional areas and lengths $2l, l,$ and $l$ respectively are connected as shown in the figure. If the ends of the rods are maintained at temperatures $100\ ^oC, 50\ ^oC,$ and $0\ ^oC$ respectively,then the temperature $\theta$ of the junction is