Three liquids of densities ${\rho }_1,$ ${\rho }_2$ $and$ $$ ${\rho }_3$ (with ${\rho }_1>{\rho }_2>{\rho }_3$), having the same value of surface tension T, rise to the same height in three identical capillaries. The angles of contact ${\theta }_1,{\theta }_2$ $and$ ${\theta }_3$ obey:

1.	\(\frac{\pi}{2}>\theta_1>\theta_2>\theta_3 \geq 0\)
2.	\(0 \leq \theta_1<\theta_2<\theta_3<\frac{\pi}{2}\)
3.	\(\frac{\pi}{2}<\theta_1<\theta_2<\theta_3<\pi\)
4.	\(\pi>\theta_1>\theta_2>\theta_3>\frac{\pi}{2}\)

 Two non-mixing liquids of densities $\rho$ and n$\rho$(n>1) are put in a container. The height of each liquid is h. A solid cylinder  floats with its axis vertical and length pL $\left(p<1\right)$ in the denser liquid. The density of the cylinder is d. The density d is equal to:

1. {2+(n+1)p}$\rho$             

2. {2+(n-1)p}$\rho$

3. {1+(n-1)p}$\rho$             

4. {1+(n+1)p}$\rho$

A wind with speed \(40~\text{m/s}\) blows parallel to the roof of a house. The area of the roof is \(250~\text{m}^2\). Assuming that the pressure inside the house is atmospheric pressure, the force exerted by the wind on the roof and the direction of the force will be: \(\left(\rho_{\text{air}}= 1.2~\text{kg/m}^3 \right)\)
1. \(4.8\times 10^{5}~\text{N}, ~\text{downwards}\)
2. \(4.8\times 10^{5}~\text{N}, ~\text{upwards}\)
3. \(2.4\times 10^{5}~\text{N}, ~\text{upwards}\)
4. \(2.4\times 10^{5}~\text{N}, ~\text{downwards}\)

The cylindrical tube of a spray pump has radius R, one end of which has n fine holes, each of radius r. If the speed of the liquid in the tube is v, then the speed of ejection of the liquid through the holes will be:
1. vR²/n²r²

2. vR²/nr²

3. vR²/n³r²

4. v²R/nr

The heart of a man pumps 5 L of blood through the arteries per minute at a pressure of 150 mm of mercury. If the density of mercury is \(13.6\times 10^3\)kg/m³ and g =10 m/s², then the power of heart in watt is:
1. 1.70
2. 2.35
3. 3.0
4. 1.50

A certain number of spherical drops of a liquid of radius r coalesce to form a single drop of radius R and volume V. If T is the surface tension of the liquid, then:\(\text { Energy }=4 V T\left(\frac{1}{r}-\frac{1}{R}\right) \text { is released } \)

An engine pumps water continuously through a hose. Water leaves the hose with a velocity \(v\) and \(m\) is the mass per unit length of the water jet. What is the rate at which kinetic energy is imparted to water?
1. $\frac{1}{2}m{v}^3$                                   

2. $m{v}^3$

3. $\frac{1}{2}m{v}^2$                                   

4. $\frac{1}{2}{m}^2{v}^2$

Two bodies are in equilibrium when suspended in water from the arms of a balance. The mass of one body is \(36\) g and its density is \(9\) g/cm³. If the mass of the other is \(48\) g, its density in g/cm³ will be:
1. $\frac{4}{3}$                                         

2. $\frac{3}{2}$

3. \(3\)                                           

4. \(5\)

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 triangular lamina of area A and height h is immersed in a liquid of density $\mathrm{\rho }$ in a vertical plane with its base on the surface of the liquid. The thrust on the lamina is:
1. $\frac{1}{2}\mathrm{A\rho gh}$                 

2. $\frac{1}{3}\mathrm{A\rho gh}$

3. $\frac{1}{6}\mathrm{A\rho gh}$                 

4. $\frac{2}{3}\mathrm{A\rho gh}$