Question

Fig shows a closed tube ABCD containing water at room temperature. End A is heated and end B is cooled. Which of the following statements is correct?

(1) Water does not circulate

(2) Water circulates in clockwise direction inside tube

(3) Water circulates in anticlockwise direction inside tube

(4) Water circulates clockwise along ADC and anticlockwise along ABC

Answer 1

(3) Water circulates in anticlockwise direction inside tube

On heating end A; density of water at A decreases whereas on cooling end B; density of water at end B increases. Therefore liquid pressure P_A and P_B at ends A and B are such that P_A < P_B . The liquid (water) moves from region of higher pressure to lower pressure. Therefore water circulation is anticlockwise direction inside tube.