An airplane of a total wing area of \(120\) ${\mathrm{m}}^2$ is in a level flight at some height. If the pressure difference between the upper and lower surface is \(2.5\) kPa, then the mass of the airplane is: (Take \(g=10\) ${\mathrm{ms}}^{-2}$)

A liquid is poured into three vessels of the same base area and equal heights as shown in the figure, then:
                                  

The area of cross-section of the wider tube shown in the figure is $800$ ${\mathrm{cm}}^2.$ If a mass of 12 kg is placed on the massless piston, then the difference in heights h of the levels of water in the two tubes will be:

The value of g at a place decreases by 2%. Then, the barometric height of mercury:

The height of a mercury barometer is 75 cm at sea level and 50 cm at the top of a hill. The ratio of density of mercury to that of air is ${10}^4$. The height of the hill is:

A vertical U-tube of uniform inner cross section, contains mercury in both its arms. A glycerin (density = 1.3 g/${\mathrm{cm}}^3$) column of length 10 cm is introduced into one of its arms. Oil of density 0.8 gm/${\mathrm{cm}}^3$ is poured into the other arm until the upper surfaces of the oil and glycerin are at the same horizontal level. Find the length of the oil column. [Density of mercury = 13.6 g/${\mathrm{cm}}^3$]  
                       
1. 10.4 cm
2. 8.2 cm
3. 7.2 cm
4. 9.6 cm

A barometer kept in a stationary elevator reads 76 cm. If the elevator starts accelerating up, the reading will be:

There are four cylindrical vessels identical in dimensions. If these are filled with equal masses of four different liquids P, Q, R, and S such that their densities are ${\mathrm{\rho }}_{\mathrm{p}}$ $>$ ${\mathrm{\rho }}_{\mathrm{Q}}$ $>$ ${\mathrm{\rho }}_{\mathrm{R}}$ $>$ ${\mathrm{\rho }}_{\mathrm{S}}$, then pressure at the base of vessel will be: 

Which of the following diagrams does not represent a streamline flow?
 

1.		2.
3.		4.

Three liquids of densities \(\mathrm{d},\) \(\mathrm{2d}\) and \(\mathrm{3d}\) are mixed in equal proportions of weights. The relative density of the mixture is: