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Properties of matter

Properties of matter

by Krishnan G -
Number of replies: 1

A 20 cm long capillary tube is dipped in water. The water rises upto 8 cm. If the entire arrangement is put in a freely falling elevator, the length of water column in the capillary tube will be

a) 8 cm

b)10 cm

c) 4 cm

d) 20 cm

Answer is given as d). Kindly explain how it is d)

In reply to Krishnan G

Re: Properties of matter

by Manish Verma -

Consider an observer inside the elevator. For this observer, there will be psuedo force acting on the water column which cacels the weight of the water column. This means that the net force upwards on the water column will be due to the surface tension. Now, this becomes the situation of the tube of insufficient length. So, the water rises upto the height of the tube.