Question

When a capillary tube is dipped in water, water rises upto `8cm` in the tube. What happends when the tube is pushed down such that its end is only `5cm` above outside water level?
A. The radius of the meniscus increases and therefore water does not overflow.
B. The radius of the water meniscus decreases and therefore does not overflow
C. The water forms a droplet on top of the tube but does not overflow
D. The water start overflowing.

Answer 1

Correct Answer - A
`h=(2sigmacostheta)/(rrhog)` or `h=(2sigmacostheta)/((Rcostheta)rhog)`
or `h=(2sigma)/(Rrhog)` or `hR=`constant
If `h` decreases, the radius of curvature of the meniscus increases.