A wooden block floats in a liquid with $40\%$ of its volume inside the liquid. When the vessel containing he liquid starts rising upwards with acceleration $a = g/2$, the percentage of volume inside the liquid is ......... $\%$
$20$
$60$
$30$
$40$
A barometer kept in an elevator reads $76 \,cm$ when it is at rest. If the elevator goes up with some acceleration, the reading will be .......... $cm$
A $U-$tube contains water and methylated spirit separated by mercury. The mercury columns in the two arms are in level with $10.0\; cm$ of water in one arm and $12.5\; cm $ of spirit in the other. if $15.0\; cm$ of water and spirit each are further poured into the respective arms of the tube, what is the difference in the levels (in $cm$) of mercury in the two arms?
(the specific gravity of spirit is $0.8.)$
The volume of an air bubble is doubled as it rises from the bottom of lake to its surface. The atmospheric pressure is $75 \,cm$ of mercury. The ratio of density of mercury to that of lake water is $\frac{40}{3}$. The depth of the lake in metre is .........
An inverted tube barometer is kept on a lift with a moving downward with a deceleration $\alpha $ . The density of mercury is $\rho$ and acceleration due to gravity is $g$ . If the atmospheric pressure be $P_0$ then
Toricelli’s barometer used mercury. Pascal duplicated it using French wine of density $984 \;kg m^{-3}$. Determine the height (in $m$) of the wine column for normal atmospheric pressure.