Question

If there were no gravity, which of the following will not be there for a fluid?
(A) Viscosity
(B) Surface tension
(C) Pressure
(D) Archimedes upward thrust

Answer 1

The gravity is linked with the weight of a body. So the parameters which are due to the weight of a fluid, they will not be there in the absence of gravity. Using the basic concepts of all of the parameters given in the options, we can figure out which are linked with the weight of the fluid.

Complete step by step solution:
We know that the viscosity of a fluid is a measure of its resistance to the relative motion between two of its adjacent layers. It is due to the molecular structure of the fluid, and not due to the gravitational force acting on the fluid. So if there was no gravity, then also the fluid will possess viscosity.
Therefore, the option A is incorrect.
We know that the surface tension in a fluid is because of the property of the free surface fluid to shrink to its minimum possible surface area. It is because of the cohesive forces on the molecules of the free surface, and not due to the gravitational force on the fluid.
Therefore, the option B is also incorrect.
The pressure in a fluid is due to its tendency to flow. A fluid confined within a fixed volume of a conductor will therefore exert forces on the inside surface of the container and hence possess pressure. This pressure is due to the weak intermolecular forces, and not due to the gravitational force on the fluid. So even in the absence of gravity, a fluid will have pressure.
Therefore, the option C is also incorrect.
We know from the Archimedes principle that the upward force on a body immersed in a fluid is equal to the weight of the fluid displaced by the body. We also know that the weight of a body is the gravitational force acting on it. So if there is no gravity, the weight of the displaced fluid will be zero. So the upward force on the immersed body will also be equal to zero.
Hence, the correct answer is option D.

Note
Do not be confused by the pressure of a column of a fluid. It is surely due to the weight of the fluid column. But this is not the only pressure inside a fluid. It only indicates that the pressure of a fluid increases with the depth. In the absence of gravity, the pressure will not change with the depth.