Sprain is caused due to stretching of

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? (in $kcal/m^2-min$)

If $f:R \to R$ and $g:R \to R$ are defined by $f(x) = 2x + 3$ and $g(x) = x^2 + 7$,then the values of $x$ such that $g(f(x)) = 8$ are

In the following common emitter circuit,if $\beta = 100$,$V_{CE} = 7\,V$,$V_{BE} = 0$,and $R_C = 2\,k\Omega$,then find the value of $I_B$ in $mA$.

In which of the following reactions,$H_2O_2$ acts as a reducing reagent?

$A$ proton, a deuteron, and an $\alpha$-particle having the same momentum enter a region of uniform electric field between the parallel plates of a capacitor. The electric field is perpendicular to the initial path of the particles. The ratio of deflections suffered by them is