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 \(g=10\) ${\mathrm{ms}}^{-2}$)

For the figures given below, the correct observation is:
              

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

A diver is \(10\) m below the surface of the water. The approximate pressure experienced by the diver is:
1. \(10^5\) Pa                   
2. \(2\times10^5\) Pa
3. \(3\times10^5\) Pa       
4. \(4\times 10^5\) Pa

If pressure at half the depth of a lake is equal to 2/3^rd the pressure at the bottom of the lake, then the depth of the lake is:

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 siphon in use is demonstrated in the following figure. The density of the liquid flowing in the siphon is 1.5 gm/cc. The pressure difference between the point P and S will be:
            

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