A rectangular film of liquid is extended from \((4~\text{cm} \times 2~\text{cm})\) to \((5~\text{cm} \times 4~\text{cm}).\) If the work done is \(3\times 10^{-4}\) J, the value of the surface tension of the liquid is:
1. \(0.250\) Nm-1
2. \(0.125\) Nm-1
3. \(0.2\) Nm-1
4. \(8.0\) Nm-1
The approximate depth of an ocean is \(2700~\text{m}\). The compressibility of water is \(45.4\times10^{-11}~\text{Pa}^{-1}\) and the density of water is \(10^{3}~\text{kg/m}^3\). What fractional compression of water will be obtained at the bottom of the ocean?
1. \(0.8\times 10^{-2}\)
2. \(1.0\times 10^{-2}\)
3. \(1.2\times 10^{-2}\)
4. \(1.4\times 10^{-2}\)
1. | surface tension. |
2. | density. |
3. | angle of contact between the surface and the liquid. |
4. | viscosity. |
A small sphere of radius r falls from rest in a viscous liquid. As a result, heat is produced due to the viscous force. The rate of production of heat when the sphere attains its terminal velocity is proportional to
1.
2.
3.
4.
A small hole of an area of cross-section \(2~\text{mm}^2\) is present near the bottom of a fully filled open tank of height \(2~\text{m}\). Taking \(g = 10~\text{m/s}^2\), the rate of flow of water through the open hole would be nearly:
1. \(6.4\times10^{-6}~\text{m}^{3}/\text{s}\)
2. \(12.6\times10^{-6}~\text{m}^{3}/\text{s}\)
3. \(8.9\times10^{-6}~\text{m}^{3}/\text{s}\)
4. \(2.23\times10^{-6}~\text{m}^{3}/\text{s}\)
A soap bubble, having a radius of \(1~\text{mm}\), is blown from a detergent solution having a surface tension of\(2.5\times 10^{-2}~\text{N/m}\). The pressure inside the bubble equals at a point \(Z_0\) below the free surface of the water in a container. Taking \(g = 10~\text{m/s}^{2}\), the density of water \(= 10^{3}~\text{kg/m}^3\), the value of \(Z_0\) is:
1. | \(0.5~\text{cm}\) | 2. | \(100~\text{cm}\) |
3. | \(10~\text{cm}\) | 4. | \(1~\text{cm}\) |
The density of ice is x gm/cc and that of water is y gm/cc. What is the change in volume in cc, when m gm of ice melts?
1. M(y-x)
2. (y-x)/m
3. mxy(x-y)
4. m(1/y-1/x)
A small sphere of radius \(r\) falls from rest in a viscous liquid. As a result, heat is produced due to the viscous force. The rate of production of heat when the sphere attains its terminal velocity is proportional to:
1. \(r^3\)
2. \(r^2\)
3. \(r^5\)
4. \(r^4\)
A body weighs 160 g in air, 130 g in water and 136 g in oil. The specific gravity of oil is
1. 0.2
2. 0.6
3. 0.7
4. 0.8
Assertion: A block of wood floats in a bucket of water in a lift. The block sink more if the lift starts accelerating up.
Reason: When lift is accelerating upward then weight is more than force of buoyancy.