Home
Class 11
PHYSICS
Assertion : The size of the needle of ...

Assertion : The size of the needle of a syringe controls flow rate better than the thumb pressure exerted by a doctor while administering an injection.
Reason : Flow rate is independent of pressure exerted by the thumb of the doctor.

A

If both assertion and reason are true and the reason is the correct explanation of the assertion.

B

If both assertion and reason are true but reason is not the correct explanation of the assertion.

C

If assertion is true but reason is false.

D

If the assertion and reason both are false.

Text Solution

Verified by Experts

The correct Answer is:
C
According to Bernoulli.s equation,
`P/rho+hg+1/2 v^2`= constant
Thus, total energy of the injectable medicine depends upon second power of the velocity and first power of the pressure. It implies that total energy of the injectable medicine has greater dependence on its velocity. Therefore, a doctor adjusts the flow of the medicine with the help of the size of the needle of the syringe (`a_1v_1=a_2v_2`) rather than the thumb pressure.
Promotional Banner

Topper's Solved these Questions

  • FLUID MECHANICS

    ERRORLESS|Exercise PAST YEARS QUESTIONS|14 Videos

  • ELASTICITY

    ERRORLESS|Exercise ASSERTION & REASON |10 Videos

  • FRICTION

    ERRORLESS|Exercise ASSERTION & REASON |8 Videos

Similar Questions

Explore conceptually related problems

Explain why (a). To keep a piece of paper horizontal, you should blow over, not under, it (b). When w try to close a water tap with our fingers, fast jets of water gush through the openings between our fingers (c). The size of the needle of a syringe controls flow rate better than the thumb pressure exerted by a doctor while administering an injection (d). A fluid flowing out of a small hole in a vessel results in a backward thrust on the vessel (e). A spinning cricket ball in air does not follow a parabolic trajectory.

Assertion : The pressure at the bottom of the sea is lesser than that near the surface. Reason : The pressure exerted by a liquid depends upon the depth of the liquid and density of the liquid.

Which factor better controls the flow rate of a liquid throught the syringe?

Torricelli was the first do devise an experiment for measuring atmospheric pressure . He took calibrated hard glass tube , 1 m in lengt and of uniform cross section , closed at one end . He filled the whole tube with dry mercury taking care than no air or water droplets remain inside the tube , closed the opposite end of the tube tightly with thumb and inverted it . He put this inverted mercury tube into a mercury through , taking care that the end of the tube remains inside the mercury through , An interesting thing was noticed . Mercury in the tube fell down at first and then stopped at a particular position . The height was 76 cm above the free surface of mercury in the through . When the given tube was inclined or lowered in the mercury trough , the vertical haight of mercury level in the tube was always found constant . Torricelli explained this by saying that the free surface of mercury in the trough . Hence , the hydrostatic pressure exerted by the trough measures the atmospheric pressure . If an additional hole is also made at P ' at the top point of the tube , then

Torricelli was the first do devise an experiment for measuring atmospheric pressure . He took calibrated hard glass tube , 1 m in lengt and of uniform cross section , closed at one end . He filled the whole tube with dry mercury taking care than no air or water droplets remain inside the tube , closed the opposite end of the tube tightly with thumb and inverted it . He put this inverted mercury tube into a mercury through , taking care that the end of the tube remains inside the mercury through , An interesting thing was noticed . Mercury in the tube fell down at first and then stopped at a particular position . The height was 76 cm above the free surface of mercury in the through . When the given tube was inclined or lowered in the mercury trough , the vertical haight of mercury level in the tube was always found constant . Torricelli explained this by saying that the free surface of mercury in the trough . Hence , the hydrostatic pressure exerted by the trough measures the atmospheric pressure . If this expriment uses water instead of mercury , then

Assertion (A) : K_(p) is always greater than K_(c) . Reason (R) : The effect of pressure is greater on the rate of reaction than the effect of concentration.

ERRORLESS-FLUID MECHANICS-ASSERTION AND REASON
  1. Assertion : To empty an oil tank, two holes are made. Reason : Oi...

    Text Solution

    |

  2. Assertion : A man sitting in a boat which is floating on a pond. If ...

    Text Solution

    |

  3. Assertion : A piece of ice floats in water, the level of water remai...

    Text Solution

    |

  4. Assertion: The velocity increases, when water flowing in broader pipe ...

    Text Solution

    |

  5. Assertion. A bubble comes from the bottom of a lake to the top. Reas...

    Text Solution

    |

  6. Assertion: The velocity of flow of a liquid is smaller when pressure i...

    Text Solution

    |

  7. Assertion: The shape of an automobile is so designed that its front re...

    Text Solution

    |

  8. Assertion : The size of the needle of a syringe controls flow rate b...

    Text Solution

    |

  9. Assertion: A fluid flowing out of a small hole in a vessel apply a bac...

    Text Solution

    |

  10. Assertion : For a floating body to be in stable equilibrium, its cen...

    Text Solution

    |

  11. Assertion: In taking into account the fact that any object which float...

    Text Solution

    |

  12. Assertion : A thin staindess steel needle can by floating on a still w...

    Text Solution

    |

  13. Assertion : Aeroplanes are made to run on the runway before take off...

    Text Solution

    |

  14. Assertion: Sudden fall of pressure of at a place indicates storm. R...

    Text Solution

    |

  15. Assertion : Inside parts of machine are jammed in winter . Reason :...

    Text Solution

    |

  16. Assertion : When two boats sails parallel in the same direction and ...

    Text Solution

    |

  17. Statement I: A raindrop after failing through some height attains a co...

    Text Solution

    |

  18. Assertion : paper pins are made to have pointed end. Reason : Beca...

    Text Solution

    |

  19. Assertion : Railways tracks are laid on small sized wooden sleepers....

    Text Solution

    |

  20. Assertion : Terminal velocity is same as the critical velocity. Re...

    Text Solution

    |