Physics NEET test arrangement, earlier year questions, answers, and solution #7

NEET PHYSICS TEST ARRANGEMENT:


QUESTION:

A capillary tube of radius 'r'  is immersed in water and the water rises it to a height h.The mass of the water in the capillary tube is 5 g. Another capillary tube of radius '2r' is immersed in water.The mass of the water  that will rise in the tube is;

[A].     2.5 g

[B].     5.0 g

[C].   10.0 g

[D].   20.0 g


ANSWER:

ANSWER - [C]


SOLUTION:

CAPILLARY RISE:

A capillary tube (glass tube) of radius 'r 'is dipped in water, the surface pulls the capillary walls in downward direction. Capillary walls pull the surface in upward direction. By the way the water in the tube will rise above the adjacent liquid level till the forces get balanced. This rises what we called it as capillary rise

Expression for capillary rise when the capillary tube is dipped in water

WHAT ARE THE TWO FORCES ACTING AT EQUILIBRIUM?

1.     First one is the weight of the water column, acting downwards.

             Weight of the water in the column = mass x gravity

                                                                    = volume x density x gravity

Expression for the capillary rise

2.     Second force is the upward force acting on water due to surface tension

                     Let T be the surface tension of the liquid.

Expression for the capillary rise

              Since the capillary pulls the surface in upward direction, the   vertical component of the surface tension is taken into account. During equilibrium the two forces should be balanced.

Exression for the capillary rise



Capillay rise- NEET physics

Mass of water rises in the capillary tube




              




Comments

Popular posts from this blog

What is motional emf? Factors on which it depends & expression for motional emf

HOW INTERNAL RESISTANCE OF A LECHLANCHE CELL IS CALCULATED USING A POTENTIOMETER ?