Question

The cylindrical tube of a spray pump has a radius R, one end of which hasn fine holes, each of radius r. If the speed of flow of the liquid in the tube is V, the speed of ejection of the liquid through the holes is 

Solution

Correct option is

 

Cross-sectional area of tube . Cross-sectional area of each hole. Therefore, cross-sectional area of n holes . If v is the speed of ejection of the liquid through the holes, then from the continuity of flow, we have

               av = AV   

  

                  

                  

SIMILAR QUESTIONS

Q1

A common hydrometer has a uniform stem graduated downwards from 0, 1, 2, ….. up to 10. When floating in pure water it reads 0 and in a liquid of relative density 1.5, it reads 10. What is the relative density of a liquid in which it reads 5?

Q2

A piece of ice, with a stone frozen inside it, is floating in water contained in a beaker. When the ice melts, the level of water in the beaker

Q3

A cubical vessel of height 1 m is full of water. What is the amount of work done is pumping water out of the vessel? Take g = 10ms–2 

Q4

The dimensions of viscosity in terms of M, L and T are

Q5

The dimensions of Reynold’s number are

Q6

A rain drop of radius r falls in air with a terminal speed vt. What is the terminal speed of a rain drop of radius 2r

Q7

Eight spherical rain drops of the same mass and radius are falling down a terminal speed of 6 cms–1. If they coalesce to form one big drop, what will be its terminal speed? Neglect the buoyancy due to air.

Q8

Water flows steadily through a horizontal pipe of a variable cross-section. If the pressure of water is p at a point where the velocity of flow is v, what is the pressure at another point where the velocity of flow is 2v being the density of water?    

Q9

In a test experiment on a model aeroplane in a wind tunnel, the flow speeds on the lower and upper surfaces of the wing are v and  respectively. If the density of air is  and the surface area of the wing is A, the dynamic lift on the wing is given by     

Q10

A piece of copper having an internal cavity weights 264 g in air and 221 g in water. The density of copper is 8.8 gm–3. What is the volume of the cavity?