A liquid filled in a container has plane meniscus. If $\mathrm{\theta }$ is the angle of contact, then:
1. $\mathrm{\theta }$ = \(0^\circ\)
2. $\mathrm{\theta }$ = \(90^\circ\)
3. $\mathrm{\theta }$ < \(90^\circ\)
4. $\mathrm{\theta }$ = \(180^\circ\)

The relative velocity of two adjacent layers of a liquid is 6 cm/s and the perpendicular distance between layers is 0.1 mm. The velocity gradient for liquid (in per second) is:

A large open tank with a square hole of side \(0.1\) cm in the wall at a depth of \(0.2\) m from the top is completely filled with a liquid. The rate of flow of liquid (in ${\mathrm{cm}}^3$/s) through the hole will be: 

The property of surface tension of the liquid is due to:

When a man sits on a boat of length 2 m and breadth 1 m floating on a lake, the boat sinks by 2 cm. The mass of the man is:

1. 25 kg

2. 40 kg

3. 60 kg

4. 80 kg

If two iron balls when fully immersed in water experience thrust force in the ratio of 1:2, then the ratio of the masses of the balls will be:
1. 1: 1
2. 1: 2
3. 2: 1
4. 1: 4

There are four cylindrical vessels identical in dimensions. If these are filled with equal masses of four different liquids P, Q, R, and S such that their densities are ${\mathrm{\rho }}_{\mathrm{p}}$ $>$ ${\mathrm{\rho }}_{\mathrm{Q}}$ $>$ ${\mathrm{\rho }}_{\mathrm{R}}$ $>$ ${\mathrm{\rho }}_{\mathrm{S}}$, then pressure at the base of vessel will be: 

When a large bubble rises from the bottom of a lake to the surface, its radius doubles. The atmospheric pressure is equal to that of a column of water of height H. The depth of the lake is:

1. H

2. 2H

3. 7H

4. 8H

The reading of a spring balance when a block is suspended from it in the air is 60 N. This reading is changed to 40 N when the block is submerged in water. The specific gravity of the block, therefore, must be:
1. 3
2. 2
3. 6
4. 3/2

A beaker full of water is placed on a spring balance. If we put our finger in water without touching the beaker, how will the reading of the balance change? [Take ${\mathrm{\rho }}_{\mathrm{finger}}$ $>$ ${\mathrm{\rho }}_{\mathrm{water}}$]
1. Increase
2. Decrease
3. Remain the same
4. Will be halved