question_answer

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                                      [AIEEE 2005]

A)  8cm                

B)       10cm

C)  4cm                

D)       20cm

Correct Answer: D

Solution :

[d] As lift accelerates downward, the liquid will rise under psuedo forcecontinuously acting in upward directions. So, liquid will rise upto entire length of the tube.

(during free fall)