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A 20cm long capillary tube is dipped in water. The water rises up to 8cm. If the entire arrangement is put in a freely falling elevator the length of water column in the capillary tube will be
(a) 10cm
(b) 8cm
(c) 20cm
(d) 4cm

Amit Saxena

12 Years agoGrade upto college level

2 Answers

Navjyot Kalra

12 Years ago

(c). Water fills the tube entirely in gravity less condition i.e, 20 cm.

Kushagra Madhukar

5 Years ago

Dear student,

Please find the answer to your question below.

During free falling, the relative acceleration between the tube and the water becomes zero as both are going downwards with the same acceleration due to gravity. Hence, w.r.t to the tube the gravitational force has no effect on water or simply put, g_eff = 0. Due to which the capillary force easily pulls the water level up to level of the tube itself.

(This can also be understood by putting g = 0 in the formula for capillary height in a tube in which we get infinity as a result, which signify whole tube being covered with capillary.)

Hence, c) will be the correct option.

Thanks and regards,

Kushagra

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