What is the concentration of $20$ volume $H_2O_2$ in $g/L$?

If $\int \frac{7x^8+8x^7}{(1+x+x^8)^2} dx = f(x) + c$,then $f(x)$ is equal to

Two bodies of masses $m$ and $4m$ are placed at a distance $r$. The gravitational potential at a point on the line joining them,where the gravitational field is zero,is

In a resonance tube experiment,a tuning fork resonates with an air column of length $12 ~cm$ and again resonates when the air column is $38 ~cm$ long. The end correction will be: (in $~cm$)

$A$ beaker full of hot water is kept in a room. If it cools from $80\,^{\circ}C$ to $75\,^{\circ}C$ in $t_1$ minutes,from $75\,^{\circ}C$ to $70\,^{\circ}C$ in $t_2$ minutes,and from $70\,^{\circ}C$ to $65\,^{\circ}C$ in $t_3$ minutes,then:

Which of the following is the order of maize?