Properties Of Solids And Liquids Question 134
Question: Assertion : The size of the needle of a syninge 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.
Options:
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.
E) If assertion is false but reason is true.
Show Answer
Answer:
Correct Answer: C
Solution:
According to Bernoulli’s equation, $ \frac{P}{\rho }+hg+\frac{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 adjust the flow of the medicine with the help of the size of the needle of the syringe $( a _{1}v _{1}=a _{2}v _{2}) $ rather than the thumb pressure.
