Secondary productivity is the rate of formation of new organic matter by:

$5.6 \ L$ of helium gas at $STP$ is adiabatically compressed to $0.7 \ L$. Taking the initial temperature to be $T_1$,the work done in the process is

Which of the following can show optical isomerism?

What are the products formed when chlorine is passed through an aqueous hypo solution?

The cathode of a photoelectric cell is changed such that the work function changes from $W_1$ to $W_2$ $(W_2 > W_1)$. If the current before and after the change are $I_1$ and $I_2$,respectively,and all other conditions remain unchanged,then (assuming $hv > W_2$):

The number of turns in the primary and secondary coils of a transformer are $50$ and $200$ respectively. If the current in the primary coil is $4 ~A$,then the current in the secondary coil is: (in $~A$)