The radius of a soap bubble is increased from R to 2 R. Work done in this process (T = surface tension) is: 

1.	24 πR2T	2.	48 πR2T
3.	12 πR2T	4.	36 πR2T

A cubical vessel of height 1 m is full of water. Find the work done in pumping out whole water.

1. 49 J

2. 490 J

3. 4900 J

4. 49000 J

The flow rate from a tap of diameter 1.25 cm is 3 lit/min. The coefficient of viscosity of water is ${10}^{-3}$ Pas. The nature of flow is :

1. Turbulent

2. Laminar

3. Neither laminar nor turbulent

4. data inadequate

Water flowing from a hose pipe fills a 15-liter container in one minute. The speed of water from the free opening of radius 1 cm is (in ms${}^{-1}$) :

1. 2.5

2. $\frac{\mathrm{\pi }}{2.5}$

3. $\frac{2.5}{\mathrm{\pi }}$

4. 5 $\mathrm{\pi }$

When a cylindrical tube is dipped vertically into a liquid the angle of contact is 140^o. When the tube is dipped with an inclination of 40^o, the angle of contact is- 

1.  $100°$  

2.  $140°$

3.  $180°$

4.    $60°$

Two liquid drops have their diameters as 1 mm and 2 mm. The ratio of excess pressure in them is :

1.  1:2

2.  2:1

3.  4:1

4.  1:4

If a soap bubble of radius 3 cm coalesce with another soap bubble of radius 4 cm under isothermal conditions, the radius of the resultant bubble formed is in cm-

1. 7

2. 1

3. 5

4. 12

$\mathrm{Water} \mathrm{flows} \mathrm{through} \mathrm{a} \mathrm{non}-\mathrm{uniform} \mathrm{tube}$
$\mathrm{of} \mathrm{area} \mathrm{of} \mathrm{cross} \mathrm{sections} \mathrm{A}, \mathrm{B}, \mathrm{and} \mathrm{C} \mathrm{whose}$
$\mathrm{values} \mathrm{are} 25, 15, \mathrm{and} 35 {\mathrm{cm}}^2 \mathrm{respectively}.$
$\mathrm{The} \mathrm{ratio} \mathrm{of} \mathrm{the} \mathrm{velocities} \mathrm{of} \mathrm{water} \mathrm{at} \mathrm{the}$
$\mathrm{sections} \mathrm{A}, \mathrm{B}, \mathrm{and} \mathrm{C} \mathrm{is}-$

1.  5:3:7

2.  7:3:5

3.  21:35:15

4.  1:1:1

Several spherical drops of a liquid each of radius r coalesce to form a single drop of radius R. If T is the surface tension, then the energy liberated will be - 

$1. 4{\mathrm{\pi R}}^3\mathrm{T} \left(\frac{1}{\mathrm{r}}-\frac{1}{\mathrm{R}}\right)$
$2. 2{\mathrm{\pi R}}^3\mathrm{T} \left(\frac{1}{\mathrm{r}}-\frac{1}{\mathrm{R}}\right)$
$3. \frac{4}{3}{\mathrm{\pi r}}^2\mathrm{T} \left(\frac{1}{\mathrm{r}}-\frac{1}{\mathrm{R}}\right)$
$4. 2\mathrm{\pi RT} \left(\frac{1}{\mathrm{R}}-\frac{1}{\mathrm{r}}\right)$

The rate of flowing of water from the orifice in a wall of a tank will be more if the orifice is:

1.  Near the bottom

2.  Near the upper end

3.  Exactly in the middle

4.  Does not depend upon the position of the orifice