Advertisements
Advertisements
प्रश्न
Explain why The size of the needle of a syringe controls flow rate better than the thumb pressure exerted by a doctor while administering an injection
Advertisements
उत्तर १
The small opening of a syringe needle controls the velocity of the blood flowing out. This is because of the equation of continuity. At the constriction point of the syringe system, the flow rate suddenly increases to a high value for a constant thumb pressure applied.
उत्तर २
For a constant height, the Bernoulli’s theorem is expressed as P +1/2 ρ v2 = Constant
In this equation, the pressure P occurs with a single power whereas the velocity occurs with a square power. Therefore, the velocity has more effect compared to the pressure. It is for this reason that needle of the syringe controls flow rate better than the thumb pressure exerted by the doctor.
APPEARS IN
संबंधित प्रश्न
(a) What is the largest average velocity of blood flow in an artery of radius 2 × 10–3 m if the flow must remain laminar? (b) What is the corresponding flow rate? (Take viscosity of blood to be 2.084 × 10–3 Pa s).
The viscous force acting between two layers of a liquid is given by \[\frac{F}{A} = - \eta\frac{dv}{dz}\]. This F/A may be called
A raindrop falls near the surface of the earth with almost uniform velocity because
A spherical ball is dropped in a long column of a viscous liquid. The speed of the ball as a function of time may be best represented by the graph
The unit of viscosity is
In a horizontal pipe of non-uniform cross-section, water flows with a velocity of 1 ms−1 at a point where the diameter of the pipe is 20 cm. The velocity of water (1.5 ms−1) at a point where the diameter of the pipe is (in cm)
Write down the expression for Stoke’s force and explain the symbols involved in it.
Two streamlines cannot cross each other. Why?
Derive Poiseuille’s formula for the volume of a liquid flowing per second through a pipe under streamlined flow.
A block of Ag of mass x kg hanging from a string is immersed in a liquid of relative density 0.72. If the relative density of Ag is 10 and tension in the string is 37.12 N then compute the mass of Ag block.
A small metal sphere of mass M and density d1, when dropped in a jar filled with liquid moves with terminal velocity after sometime. The viscous force acting on the sphere is (d2 = density of liquid and g = gravitational acceleration)
From amongst the following curves, which one shows the variation of the velocity v with time t for a small-sized spherical body falling vertically in a long column of a viscous liquid.
Clouds float in the air due to ______.
With increase in temperature, the viscosity of ______.
- gases decreases.
- liquids increases.
- gases increases.
- liquids decreases.
The velocity of a small ball of mass 0.3 g and density 8 g/cc when dropped in a container filled with glycerine becomes constant after some time. If the density of glycerine is 1.3 g/cc, then the value of viscous force acting on the ball will be x × 10-4 N, and the value of x is ______.
[use g = 10 m/s2]
State the formula and S.I. units of coefficient of viscosity.
Define velocity gradient.
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?
