An air bubble doubles its radius on raising from the bottom of water reservoir to the surface of water in it. if the atmospheric pressure is equal to 10 m of water, the height of water in the reservoir is:
A) 10 m
B) 20 m
C) 70 m
D) 80 m
Correct Answer:
C
Solution :
From relation, \[h=({{n}^{3}}-1)H,n=2\] \[h=[{{(2)}^{3}}-1]\times 10=70\,\,m\]