SCERT Maharashtra solutions for Physics [English] 12 Standard HSC chapter 2 - Mechanical Properties of fluids [Latest edition]

Insect moves over the surface of water because of ______.

The water droplets are spherical in free fall due to ______ 

The surface tension of a liquid at critical temperature is ______ 

Unit of the coefficient of viscosity is ______ 

Two capillary tubes of radii 0.6 cm and 0.3 cm are dipped in the same liquid. The ratio of heights through which the liquid will rise in the tubes is ______.

The energy stored in a soap bubble of diameter 6 cm and T = 0.04 N/m is nearly ______.

Two stones with radii 1:2 fall from a great height through the atmosphere. Their terminal velocities are in the ratio ______ 

What is the surface film? 

What are cohesive forces?

What will be the shape of the liquid meniscus for the obtuse angle of contact? 

What is the net weight of a body when it falls with terminal velocity through a viscous medium?

A square metal plate of area 100 cm² moves parallel to another plate with a velocity of 10 cm/s, both plates immersed in water. If the viscous force is 200 dyne and the viscosity of water is 0.01 poise, what is the distance between them?   

The relative velocity between two parallel layers of water is 8 cm/s and the perpendicular distance between them is 0.1 cm. Calculate the velocity gradient. 

Water rises to a height of 20 mm in a capillary tube. If the radius made 1/3^rd of its previous value, to what height will the water now rise in the tube?  

State properties of an ideal fluid.

Compare streamline flow and Turbulent flow.

Define surface tension 

Define angle of contact.

Calculate the rise of water inside a clean glass capillary tube of radius 0.1 mm, when immersed in water of surface tension 7 × 10^-2 N/m. The angle of contact between water and glass is zero, the density of water = 1000 kg/m³, g = 9.8 m/s².

A raindrop of radius 0.3 mm falls through the air with a terminal velocity of 1 m/s. The viscosity of air is 18 x 10⁻⁶ Ns /m². Find the viscous force on the raindrop.  

Two soap bubbles have a radius in the ratio of 2:3. Compare the works done in blowing these bubbles.  

Explain the phenomena of surface tension on the basis of molecular theory.

Obtain an expression for the capillary rise or fall using the forces method.  

State Stoke’s law and give two factors affecting angle of contact.  

Twenty-seven droplets of water, each of radius 0.1 mm coalesce into a single drop. Find the change in surface energy. Surface tension of water is 0.072 N/m.

A u-tube is made up of capillaries of bore 1 mm and 2 mm respectively. The tube is held vertically and partially filled with a liquid of surface tension 49 dyne/cm and zero angles of contact. Calculate the density of the liquid, if the difference in the levels of the meniscus is 1.25 cm. take g = 980 cm/s²  

A rectangular wireframe of size 2 cm x 2 cm, is dipped in a soap solution and taken out. A soap film is formed, if the size of the film is changed to 3 cm x 3 cm, Calculate the work done in the process. The surface tension of the soap film is 3 x 10^-2 N/m.

Derive the relation between surface tension and surface energy per unit area.

Derive Laplace’s law for spherical membrane of bubble due to surface tension.

Derive an expression for the terminal velocity of the sphere falling under gravity through a viscous medium.