2025 Exam Questions
Q Using Newton’s law of viscosity for streamline flow, derive an expression for coefficient of viscosity.
Q. In Bernoulli’s theorem, which of the following is constant?
(A) Linear momentum
(B) Angular momentum
(C) Mass
(D) Energy
Q. At what temperature the surface tension of a liquid becomes zero?
Q. Diameter of a water drop is 0.6 mm . Calculate the pressure inside a liquid drop. ( \mathrm{T}=72 \mathrm{dyne} / \mathrm{cm} , atmospheric pressure =1.013 \times 10^{5} \mathrm{~N} / \mathrm{m}^{2} )
2024 Exam Questions
Q. The dimensional formula of surface tension is______.
(a) \left[L^{-1}M^1T^{-2}\right]
(b) \left[L^2M^1T^{-2}\right]
(c) \left[L^1M^1T^{-1}\right]
(d) \left[L^0M^1T^{-2}\right]
Q. Why a detergent powder is mixed with water to wash clothes?
Q. A horizontal force of O.5N is required to move a metal plate of area 10-2m2 with a velocity of 3 x 10¯3 m/s, when it rests on 0.5 X 10-3 m thick layer of glycerin. Find the coefficient of viscosity of glycerin.
Q. Define surface energy of the liquid. Obtain the relation between the surface energy and surface tension.
2023 Exam Questions
Q. If ‘θ’ represents the angle of contact made by a liquid which completely wets the surface of the container then_____.
(A) θ = 0
(B) 0<\theta<\frac\pi2
(C) \theta=\frac\pi2
(D) \frac\pi2<\theta<\pi
Q. Obtain the relation between surface energy and surface tension.
Q. Define coefficient of viscosity. State its formula and S.I. units.
Q. Calculate the work done in blowing a soap bubble to a radius of 1 cm. The surface tension of soap solution is 2.5 x 10-2 N/m.
2022 Exam Questions
Q. A liquid rises in glass capillary tube upto a height of 2.5 cm at room temperature. If another glass capillary tube having radius half that of the earlier tube is immersed in the same liquid, the rise of liquid in it will be____.
(A) 1.25 cm
(B) 2.5 cm
(C) 5 cm
(D) 10 cm
Q. Raindrops are spherical in shape because of _____.
(A) Surface tension
(B) capillarity
(C) downword motion
(D) acceleration due to gravity
Q. Define angle of contact. State any two properties of angle of contact.
Q. What is capillarity? State any two uses of capillarity.
Q. State the formula for critical velocity in terms of Reynold’s number for a flow of a fluid.
Q. Derive an expression for terminal velocity of a spherical object falling under gravity through a viscous medium.
Q. Eight droplets of water each of radius 0.2 mm coalesce into a single drop. Find the decrease in the surface area.
Q. Find the difference of pressure between inside and outside of a spherical water drop of radius 2 mm, if surface tension of water is 73 x 10-3 N/m.
