A submarine has a window of area $30 \times 30 \,cm ^2$ on its ceiling and is at a depth of $100 \,m$ below sea level in a sea. If the pressure inside the submarine is maintained at the sea-level atmosphere pressure, then the force acting on the window is ............. $N$ (consider density of sea water $=1.03 \times 10^3 \,kg / m ^3$, acceleration due to gravity $=10 \,m / s ^2$ )
$0.93 \times 10^5$
$0.93 \times 10^3$
$1.86 \times 10^5$
$1.86 \times 10^3$
Explain that how does an open ended tube manometer measure pressure.
What does it mean when a height of a barometer is falling ?
A cylindrical furnace has height $(H)$ and diameter $(D)$ both $1 \mathrm{~m}$. It is maintained at temperature $360 \mathrm{~K}$. The air gets heated inside the furnace at constant pressure $P_a$ and its temperature becomes $T=360 \mathrm{~K}$. The hot air with density $\rho$ rises up a vertical chimney of diameter $d=0.1 \mathrm{~m}$ and height $h=9 \mathrm{~m}$ above the furnace and exits the chimney (see the figure). As a result, atmospheric air of density $\rho_a=1.2 \mathrm{~kg} \mathrm{~m}^{-3}$, pressure $P_a$ and temperature $T_a=300 \mathrm{~K}$ enters the furnace. Assume air as an ideal gas, neglect the variations in $\rho$ and $T$ inside the chimney and the furnace. Also ignore the viscous effects.
[Given: The acceleration due to gravity $g=10 \mathrm{~ms}^{-2}$ and $\pi=3.14$ ]
(image)
($1$) Considering the air flow to be streamline, the steady mass flow rate of air exiting the chimney is
. . . . .$\mathrm{gm} \mathrm{s}^{-1}$.
($2$) When the chimney is closed using a cap at the top, a pressure difference $\Delta P$ develops between the top and the bottom surfaces of the cap. If the changes in the temperature and density of the hot air, due to the stoppage of air flow, are negligible then the value of $\Delta P$ is. . . . .$\mathrm{Nm}^{-2}$.
If pressure at half the depth of a lake is equal to $2/3$ pressure at the bottom of the lake then what is the depth of the lake ........ $m$
If solid will break under pressure greater than $13\ atm$ and that solid has a specific gravity of $4$ , what is the maximum height of a cylinder made from the solid that can be built at the earth's surface ? (Note: $1\ atm$ = $10^5\ Pa$ .) ......... $m$