Inverted pyramid is found in

$A$ student measures the distance traversed in free fall of a body,initially at rest in a given time. He uses this data to estimate $g$,the acceleration due to gravity. If the maximum percentage errors in measurement of the distance and the time are $e_1$ and $e_2$ respectively,the percentage error in the estimation of $g$ is

Two sources of equal emf $E$ are connected in series to an external resistance $R$. The internal resistances of the two sources are $R_1$ and $R_2$ $(R_2 > R_1)$. If the potential difference across the source having internal resistance $R_2$ is zero,then the value of $R$ is:

If a gas is compressed isothermally,then the r.m.s. velocity of the molecules

Which of the following is an unsuitable habitat for algae?

The air density at Mount Everest is less than that at sea level. Mountaineers find that for one trip lasting a few hours,the extra oxygen needed corresponds to $30,000 \ cc$ at sea level (pressure $1 \ atm$,temperature $27^{\circ}C$). Assuming that the temperature around Mount Everest is $-73^{\circ}C$ and that the oxygen cylinder has a capacity of $5.2 \ L$,the pressure at which $O_2$ must be filled in the cylinder is ..... $atm$.