Technical Based Test Test 1 Nddc Scholarship
Question 21
Viscosity is a transport phenomenon explained using the concept of transfer of
Correct answer: (d) momentum
Viscosity arises from the transfer of momentum between adjacent fluid layers moving at different velocities.
Not clear enough?
Question 22
Viscosity is closely similar to
Correct answer: (c) friction
Viscosity is the fluid equivalent of friction, resisting relative motion between layers of the fluid.
Not clear enough?
Question 23
A drop of oil is placed on the surface of water. Which of the following statements is correct?
Correct answer: (a) it will spread as a thin layer
Oil has a lower surface tension than water, so it spreads out over the surface to form a thin film.
Not clear enough?
Question 24
In a human body the blood pressure is the greatest at
Correct answer: (d) feet
Blood pressure is greatest at the feet due to the effect of gravity on the column of blood in the body.
Not clear enough?
Question 25
The value of Reynolds number signifies
Correct answer: (a) whether the flow is stream lined or turbulent
The Reynolds number helps predict flow type: low values indicate laminar (streamlined) flow, and high values indicate turbulent flow.
Not clear enough?
Question 26
The unit of coefficient of viscosity is
Correct answer: (d) Ns/m²
The SI unit of coefficient of viscosity (η) is pascal-second (Pa·s), which is equivalent to N·s/m².
Not clear enough?
Question 27
The surface water in a lake is just going to freeze. What is the temperature at the bottom of the lake?
Correct answer: (c) 4°C
Water is densest at 4∘C4^\circ\text{C}, so before the surface freezes, the bottom of the lake remains at this temperature.
Not clear enough?
Question 28
Water evaporates under atmospheric pressure. Without changing the temperature the same water is placed under partial vacuum. Then the rate of evaporation
Correct answer: (a) will increase
Lowering the pressure reduces the boiling point, making it easier for molecules to escape the surface, thus increasing the evaporation rate.
Not clear enough?
Question 29
Universal gas constant has the unit of
Correct answer: (c) J/mol·K
The universal gas constant R has SI units of joules per mole per kelvin.
Not clear enough?
Question 30
When water is heated from 0°C to 10°C, its volume
Correct answer: (c) first decreases and then increases
Water contracts as it is heated from \(0^\circ\text{C}\) to \(4^\circ\text{C}\) (becoming denser), then expands when heated further to \(10^\circ\text{C}\).
Not clear enough?
You might like
For the restricted and internet security zones, you should disable __________ to prevent malicious code from running automatically.
A gas at a volume of V\(_0\) in a container at pressure p\(_0\) is compressed to one-fifth of its volume. What will be its pressure if the magnitude of its original temperature T is constant?
A document which entitles its holder to the goods named on it, which is stored in a specific warehouse is called________
Pointing towards a man a lady said, “His brother is my mother’s only daughter’s husband’s son’s father’. How is the man related to the lady’s husband ?