The radiant energy from the sun incident normally at the surface of the earth is $20 \, kcal/m^2-min$. What would have been the radiant energy incident normally on the earth if the sun had a temperature twice of the present one? ........... $kcal/m^2-min$

The type of bond connecting two nucleotides is

When a certain circuit consisting of a constant $emf$ $E$,an inductance $L$,and a resistance $R$ is closed,the current in it increases with time according to curve $1$. After one parameter ($E$,$L$,or $R$) is changed,the increase in current follows curve $2$,when the circuit is closed a second time. Which parameter was changed and in what direction?

Which of the following would produce a buffer solution when mixed in equal volumes?

Considering ideal gas behavior, the expansion work done $(in kJ )$ when $144 g$ of water is electrolyzed completely under constant pressure at $300 K$ is $...$ .
Use: Universal gas constant $( R )=8.3 J K ^{-1} mol^{-1}$; Atomic mass $($in amu$)$: $H =1, O =16$

During the change of $O_2$ to $O_2^-$ ion,the electron adds to which one of the following orbitals?