Three liquids of densities \(d,\) \(2d\) and \(3d\) are mixed in equal proportions of weights. The relative density of the mixture is:
1. | \(11d \over 7\) | 2. | \(18d \over 11\) |
3. | \(13d \over 9\) | 4. | \(23d \over 18\) |
The pressure of water in a water pipe when tap is opened and closed are respectively \(3\times10^5\) Nm–2 and \(3.5\times10^5\) Nm–2. With open tap, the velocity of water flowing is:
1. \(10\) ms–1
2. \(5\) ms–1
3. \(20\) ms–1
4. \(15\) ms–1
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 small spherical solid ball is dropped in a viscous liquid. Its journey in the liquid is best described in the figure by:
1. | curve A | 2. | curve B |
3. | curve C | 4. | curve D |
The height of a mercury barometer is 75 cm at sea level and 50 cm at the top of a hill. The ratio of density of mercury to that of air is . The height of the hill is:
1. | 250 m | 2. | 2.5 km |
3. | 1.25 km | 4. | 750 m |
The value of g at a place decreases by 2%. Then, 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 cm. If the elevator starts accelerating up, the reading will be:
1. | zero. | 2. | equal to 76 cm. |
3. | more than 76 cm. | 4. | less than 76 cm. |
The following fig. shows the flow of liquid through a horizontal pipe. Three tubes A, B and C are connected to the pipe. The radii of the tubes A, B and C at the junction are respectively 2 cm, 1 cm and 2 cm. It can be said that the:
1. | Height of the liquid in the tube A is maximum |
2. | Height of the liquid in the tubes A and B is the same |
3. | Height of the liquid in all the three tubes is the same |
4. | Height of the liquid in the tubes A and C is the same |
There is a hole in the bottom of a tank having water. If the total pressure at the bottom is 3 atm ( ), then the velocity of water flowing from the hole is:
1. | \(\sqrt{400}~~\text{m/s}\) | 2. | \(\sqrt{600}~~\text{m/s}\) |
3. | \(\sqrt{60}~~\text{m/s}\) | 4. | None of these |
A spherical ball of radius \(r\) is falling in a viscous fluid of viscosity \(\eta\) with a velocity \(v.\) The retarding viscous force acting on the spherical ball is:
1. | inversely proportional to \(r\) but directly proportional to velocity \(v.\) |
2. | directly proportional to both radius \(r\) and velocity \(v.\) |
3. | inversely proportional to both radius \(r\) and velocity \(v.\) |
4. | directly proportional to \(r\) but inversely proportional to \(v.\) |