A rectangular film of liquid is extended from \((4~\text{cm} \times2 ~\text{cm})\) to \((5 ~\text{cm}\times 4 ~\text{cm})\). If the work done is \(3 \times 10^{-4}~\text{J},\) the value of the surface tension of the liquid is: 
1. \(0.25\) N/m
2. \(0.125\) N/m
3. \(0.2\) N/m
4. \(8.0\) N/m

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
 

If pressure at half the depth of a lake is equal to 2/3 pressure at the bottom of the lake ,then what is the depth of the lake ?

1. 10 m                         
2. 20 m
3. 60 m                           
4. 30 m

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. \(\dfrac{2}{3}\)

2. \(\dfrac{4}{3}\)

3. \(\dfrac{3}{2}\)

4. \(3\)

The value of g at a place decreases by 2%. The barometric height of mercury
1. Increases by 2%

2. Decreases by 2%

3. Remains unchanged

4. Sometimes increases and sometimes decreases
 

A barometer kept in a stationary elevator reads \(76~\text{cm}\). If the elevator starts accelerating up, the reading will be:
1. Zero
2. Equal to \(76~\text{cm}\)
3. More than \(76~\text{cm}\)
4. Less than \(76~\text{cm}\)