JEE Main 12 Jan 2019 Evening Question 5
Question: A long cylindrical vessel is half filled with a liquid. When the vessel is rotated about its own vertical axis, the liquid rises up near the wall. If the radius of vessel is 5 cm and its rotational speed is 2 rotations per second, then the difference in the heights between the centre and the sides, in cm, will be [JEE Main Online Paper Held On 12-Jan-2019 Evening]
Options:
A) 0.4
B) 2.0
C) 0.1
D) 1.2
Show Answer
Answer:
Correct Answer: B
Solution:
- The linear speed of the liquid at the sides is $ r\omega $ .
So, the difference in height is given as follows: $ 2gh=w^{2}r^{2} $
$ \Rightarrow $ $ h=\frac{{{(2\times 2\pi )}^{2}}{{(5\times {10^{-2}})}^{2}}}{2\times 10}\approx 0.02m $
