A capillary tube of radius \(r\) is immersed in water and water rises in it to a height \(h.\) The mass of the water in the capillary is \(5\) g. Another capillary tube of radius \(2r\) is immersed in water. The mass of water that will rise in this tube is:
1. \(5.0\) g
2. \(10.0\) g
3. \(20.0\) g
4. \(2.5\) g

With an increase in temperature, the viscosity of liquid and gas, respectively will:

In a horizontal pipe of non-uniform cross-section, water flows with a velocity of 1 m s${}^{-1}$ at a point where the diameter of the pipe is 20 cm. The velocity of water (m s${}^{-1}$) at a point where the diameter of the pipe is 5 cm is:
1. 8
2. 16
3. 24
4. 32

Two small spherical metal balls, having equal masses, are made from materials of densities \(\rho_1\) and \(\rho_2\) such that ${\rho }_1=8{\rho }_2$ and having radii of \(1\) mm and \(2\) mm, respectively. They are made to fall vertically (from rest) in a viscous medium whose coefficient of viscosity equals $\eta$ and whose density is \(0.1\)${\rho }_2$. The ratio of their terminal velocities would be:
1. $\frac{79}{72}$

2. $\frac{19}{36}$

3. $\frac{39}{72}$

4. $\frac{79}{36}$

The speed of flow past the lower surface of a wing of an aeroplane is 50 m/s. What speed of flow over the upper surface will give a dynamic lift of 1000 Pa? (Density of air = 1.3 kg/m³):
        
1. 25.55 m/s

2. 63.55 m/s

3. 13.25 m/s

4. 6.355 m/s

Small droplets of liquid are usually more spherical in shape than the larger drops of the same liquid because:

The velocity of a small ball of mass m and density $\mathrm{\rho }$ when dropped in a container filled with glycerin of density $\sigma$ becomes constant after sometime. The viscous force acting on the ball in the final stage is:-

1. $\mathrm{mg}\left(\frac{\mathrm{\sigma }}{\mathrm{\rho }}\right)$

2. $\mathrm{mg}\left(1+\frac{\mathrm{\sigma }}{\mathrm{\rho }}\right)$

3. $\mathrm{mg}\left(1-\frac{\mathrm{\sigma }}{\mathrm{\rho }}\right)$

4. mg

Water flows through a horizontal tube as shown in figure. If the difference in heights of water column in vertical tubes is 80 cm and the area of cross-section at A and B are 5 cm² and 3 cm² respectively, then the rate of flow of water at A( in cc/sec) is:-

[$Take$ $g$ $=10$ $m/s^2$]

1. $15\times {10}^2$

2. $15\times {10}^3$

3. 150

4. None of these

Two soap bubbles are connected by a tube as shown in the figure. Which of the following statement is true?
                                  

The wettability of a surface by a liquid depends primarily on: