The velocity of kerosene oil in a horizontal pipe is 5 m/s. If $\mathrm{g}=10\mathrm{m}/{\mathrm{s}}^2$, then the velocity head of oil will be:
1. 1.25 m
2. 12.5 m
3. 0.125 m                             
4. 125 m

An L-shaped tube with a small orifice is held in a water stream as shown in fig. The upper end of the tube is 10.6 cm above the surface of water. What will be the height of the jet of water coming from the orifice? Velocity of water stream is 2.45 m/s.
         

1. Zero                                         
2. 20.0 cm                   
3. 10.6 cm                                   
4. 40.0 cm
 

An incompressible fluid flows steadily through a cylindrical pipe which has a radius 2r at point A and a radius r at B further along the flow direction. If the velocity at point A is v, its velocity at point B is:
1. 2v                               
2. v
3. v/2                               
4. 4v

 A wooden block with a coin placed on its top, floats in water as shown in fig. The distance l and h are shown there. After some time the coin falls into the water. Then:
                      

A wooden stick 2 m long is floating on the surface of the water. The surface tension of water is 0.07 N/m. By putting soap solution on one side of the stick, the surface tension is reduced to 0.06 N/m. The net force on the stick due to surface tension will be:

The energy needed to break a drop of radius R into n drops of radii r is given by:

1. $4\mathrm{\pi T}({\mathrm{nr}}^2-{\mathrm{R}}^2)$

2. $\frac{4}{3}\mathrm{\pi }({\mathrm{r}}^3\mathrm{n}-{\mathrm{R}}^2)$

3. $4\mathrm{\pi T}({\mathrm{R}}^2-{\mathrm{nr}}^2)$

4. $4\mathrm{\pi T}({\mathrm{r}}^2\mathrm{n}+{\mathrm{R}}^2)$

Water rises in a capillary tube to a certain height such that the upward force due to surface tension is balanced by $75\times {10}^{-4}$ $\mathrm{N}$ force due to the weight of the liquid. If the surface tension of water is $6\times {10}^{-2}$ ${\mathrm{Nm}}^{-1}$, the inner circumference of the capillary must be:

1. $1.25\times {10}^{-2}$ $\mathrm{m}$ 

2. $0.50\times {10}^{-2}$ $\mathrm{m}$

3. $6.5\times {10}^{-2}$ $\mathrm{m}$

4. $12.5\times {10}^{-2}$ $\mathrm{m}$

Water rises to a height \(\mathrm{h}\) in a capillary at the surface of earth. On the surface of the moon, the height of water column in the same capillary will be:
1. \(\mathrm{6h}\)                           
2. $\frac{1}{6}\mathrm{h}$
3.  \(\mathrm{h}\)                             
4. \(\mathrm{zero}\)

In a capillary tube experiment, a vertical 30 cm long capillary tube is dipped in water. The water rises up to a height of 10 cm due to capillary action. If this experiment is conducted in a freely falling elevator, the length of the water column becomes:
1. 10 cm
2. 20 cm
3. 30 cm
4. Zero

There is a horizontal film of soap solution. On it, a thread is placed in the form of a loop. The film is pierced inside the loop and the thread becomes a circular loop of radius R. If the surface tension of the loop is T, then what will be the tension in the thread?

1. ${\mathrm{\pi R}}^2/\mathrm{T}$

2. ${\mathrm{\pi R}}^2\mathrm{T}$

3. $2\mathrm{\pi RT}$

4. $2\mathrm{RT}$