The mass defect for the nucleus of helium is $0.0303 \, a.m.u.$ What is the binding energy per nucleon for helium in $MeV$?

Which of the following enzymes hydrolyzes the internal phosphodiester bonds in a polynucleotide chain?

Nitrobenzene on reduction using zinc in alkaline medium results in $X$. The number of $\sigma$ and $\pi$ bonds in $X$ is

$\int \frac{dx}{1-\cos x-\sin x}$ is equal to

Match the following:

Column-$I$	Column-$II$
$(1)$ Oxytocin	$(p)$ Stimulates the secretion of thyroid hormone
$(2)$ Vasopressin	$(q)$ Act on the smooth muscles
$(3)$ $FSH$ and androgens	$(r)$ Stimulates resorption of water
$(4)$ $TSH$	$(s)$ Regulate spermatogenesis

In a transistor circuit,when the base current is increased by $50 \mu A$ keeping the collector voltage fixed at $2 \ V$,the collector current increases by $1 \ mA$. The current gain of the transistor is