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 \(v.\) |
The pans of a physical balance are in equilibrium. If Air is blown under the right hand pan then the right hand pan will:
1. | Move up | 2. | Move down |
3. | Move erratically | 4. | Remain at the same level |
A tank is filled with water up to a height \(\mathrm H.\) Water is allowed to come out of a hole \(\mathrm P\) in one of the walls at a depth \(\mathrm D\) below the surface of water. Express the horizontal distance \(\mathrm{x}\) in terms of \(\mathrm H\) and \(\mathrm {D}\text :\)
1.
2.
3.
4.
If the excess pressure inside a soap bubble is balanced by an oil column of height of \(2\) mm, then the surface tension of the soap solution will be: (radius of the soap bubble, \(r=1\) cm and density of oil, \(d=0.8\) gm/cm3)
1. \(3.9\) N/m
2.
3.
4. \(3.9\) dyne/m
If the surface tension of water is 0.06 , then the capillary rise in a tube of diameter 1 mm is: \((\theta = 0^{\circ})\)
1. 1.22 cm
2. 2.44 cm
3. 3.12 cm
4. 3.86 cm