HSC Science (General) 12th Standard Board Exam - Maharashtra State Board Question Bank Solutions for Physics

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. 

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.  

State the formula for critical velocity in terms of Reynold's number for a flow of a fluid.

What are the two main causes of turbulent flow?

Define the coefficient of viscosity.

State the formula and S.I. units of coefficient of viscosity.

Define velocity gradient.

An incompressible liquid is flowing through a uniform cross-sectional tube with a velocity 12 cm/ s. If the thickness of liquid layer is 0.8 cm, what is the velocity gradient of that flow of liquid?

State and explain Newton's law of viscosity.

A force of 0.01 N is required to move a flat glass plate of area of 10 cm² with a uniform velocity of 1 cm/ s over the surface of a liquid 2 mm thick. If the coefficient of viscosity of the liquid is 20 poise, the velocity gradient in the liquid layer is ______.

The dimensions of coefficient of viscosity are ______.

A water pipe with diameter of 5.0 cm is connected to another pipe of diameter 2.5 cm. How would the speeds of the water flow compare?

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

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

State Stokes' law and an expression for the magnitude of the viscous force.

Why does the speed of a liquid increase and its pressure decrease when a liquid passes through a constriction in a horizontal pipe?

Bernoulli's equation for an ideal fluid in streamline flow may be written as

Bernoulli's theorem is based on the conservation of