The density of ocean water varies with depth. This is due to:
1. elasticity
2. viscosity
3. surface tension
4. all of the above
1. | \(a\hat i\) | 2. | \(-a\hat i\) |
3. | \(a\hat i+b\hat j\) | 4. | \(-a\hat i+b\hat j\) |
With a rise in temperature:
1. | surface tension of water decreases. |
2. | viscosity of water decreases. |
3. | viscosity of air decreases. |
4. | viscosity of air increases. |
1. | \(\dfrac{4S}{r}\) | 2. | \(\dfrac{8S}{3r}\) |
3. | \(\dfrac{8S}{r}\) | 4. | \(\dfrac{16S}{3r}\) |
1. | As the platelets enter a constriction, the platelets get squeezed closer together in the narrow region and hence the fluid pressure must rise there. |
2. | As the platelets enter a constriction, pressure is lower there. |
3. | The artery's cross-section area is smaller in the constriction and thus the pressure must be larger there because pressure equals the force divided by area. |
4. | The pressure is the same in all the parts of the artery. |
A block of wood is immersed in water (assume that the wood is impervious to water), and it floats half immersed. It is placed in an elevator which is accelerating upward. Then,
1. | the block floats, slightly more of it out of the water. |
2. | the block floats, slightly less of it out of the water. |
3. | the block floats, half-immersed. |
4. | the block sinks completely. |
1. | \(\dfrac{R}{6t}\) | 2. | \(\dfrac{R}{3t}\) |
3. | \(\dfrac{6t}{R}\) | 4. | \(\dfrac{3t}{R}\) |
A cube floats both in water and in a liquid of specific gravity of \(0.8\). Therefore,
a. | the apparent weight of the cube is the same in water and in liquid. |
b. | the cube has displaced an equal volume of water and liquid while floating. |
c. | the cube has displaced an equal weight of water and liquid while floating. |
d. | if some weights are placed on the top surface of the cube to make it just sink, the load in case of water will be \(0.8\) times of that to be used in case of liquid. |
1. | (a) and (c) both are correct. |
2. | only (d) is correct. |
3. | (a) and (b) both are correct. |
4. | (a), (b), and (c) are correct. |
A small tube containing air at atmospheric pressure (\(P=76\) cm of Hg) has a mercury column of the length of \(19\) cm. The tube is initially horizontal, then it is turned so that the open end is upward and the tube is vertical.
The length of the trapped air column:
1. | \(10\) cm. | increases by
2. | \(10\) cm. | decrease by
3. | \(8\) cm. | increases by
4. | \(8\) cm. | decreases by