Question

In a stationary lift water rises to height 'h' in a capillary tube. If lift starts to move upwards with uniform acceleration $g/2$, height of water in capillary is ___________.

• A. $\frac{3}{2}h$
• B. h
• C. $\frac{2}{3}h$
• D. $\frac{h}{2}$

Answer 1

The correct option is C $\frac{2}{3}h$

If the lift is moving with and upward accelration of $\frac{g}{2}$, the apparent gravity in that frame is $\frac{3g}{2}$.
$h=\frac{2Tcos\theta }{\rho gr}{h}_1=\frac{2Tcos\theta }{\rho \left(\frac{3}{2}g\right)r}=\frac{2}{3}\left(\frac{2Tcos\theta }{\rho gr}\right)=\frac{2}{3}h$