When $H_2SO_4$ reacts with $PCl_5$,the obtained product is/are:

$(a+b) \cdot (b+c) \times (a+b+c)$ is equal to

$A$ tower,of $x$ metres high,has a flagstaff at its top. The tower and the flagstaff subtend equal angles at a point distant $y$ metres from the foot of the tower. Then,the length of the flagstaff (in metres) is:

If $\alpha, \beta, \gamma$ are the roots of the equation $x^3-6x^2+11x-6=0$ and if $a=\alpha^2+\beta^2+\gamma^2$,$b=\alpha\beta+\beta\gamma+\gamma\alpha$ and $c=(\alpha+\beta)(\beta+\gamma)(\gamma+\alpha)$,then the correct inequality among the following is

$x = \log \left( \frac{1}{y} + \sqrt{1 + \frac{1}{y^2}} \right) \Rightarrow y$ is equal to

The binding energy of deuteron is $2.2 \, MeV$ and that of ${}_2^4He$ is $28 \, MeV$. If two deuterons are fused to form one ${}_2^4He$ nucleus,then the energy released is ......... $MeV$.