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.	\(\dfrac{vR^2}{n^2r^2}\)	2.	\(\dfrac{vR^2}{nr^2}\)
3.	\(\dfrac{vR^2}{n^3r^2}\)	4.	\(\dfrac{v^2R}{nr}\)

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

Water rises to a height h in capillary tube . If the length of capillary tube above the surface of water is made less than h, then

(1) water rises upto the tip of capillary tube and then starts overflowing like a fountain

(2) water rises upto the top of capillary tube and stays there without overflowing

(3) water rises upto a point a little below the top and stays there

(4) water does not rise at all

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. \(\dfrac{1}{2} m v^{3}\)                                   

2. \(m v^{3}\)

3. \(\dfrac{1}{2} m v^{2}\)                                   

4. \(\dfrac{1}{2} m^{2} v^{2}\)

Two bodies are in equilibrium when suspended in water from the arms of a balance. The mass of one body is \(36~\text g\) and its density is \(9~\text{g/cm}^3.\) If the mass of the other is \(48~\text g,\) its density in \((\text{g/cm}^3)\) will be:
1. \(\frac{4}{3}\)
2. \(\frac{3}{2}\)
3. \(3\)
4. \(5\)

An inverted bell lying at the bottom of a lake 47.6 m deep has 50 cm³ of air trapped in it. The bell is brought to the surface of the lake. The volume of the trapped air will be (atmospheric pressure = 70 cm of Hg and density of Hg = 13.6 g/cm³) 
(1) 350 cm³                               

(2) 300 cm³

(3) 250 cm³                               

(4) 22 cm³

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

(1) ${10}^5 \mathrm{N}/\mathrm{m}$                                 

(2) $2\times {10}^5 \mathrm{N}/\mathrm{m}$

(3) Zero                                       

(4) Infinity 

The height of a mercury barometer is 75 cm at sea level and 50 cm at the top of a hill. Ratio of density of mercury to that of air is ${10}^4$. The height of the hill is
(1) 250 m                             

(2) 2.5 km

(3) 1.25 km                           

(4) 750 m

Equal masses of water and a liquid of relative density 2 are mixed together, then the mixture has a density of
(1) 2/3                                 

(2) 4/3

(3) 3/2                                 

(4) 3