The radii of the base of two cylindrical tins, P and Q are r and 2r respectively. If the water level in p is 10cm high, would be the height of the same quantity of water in Q?
-
A.
2.5cm -
B.
5.0cm -
C.
7.5cm -
D.
20.0cm
Correct Answer: Option A
Explanation
volume of cylinder = (pi r^2h)
volume of cylinder p = (pi r^2 times 10)
= 10(pi r^2)
volume of cylinder Q = (pi (2r)^2 h)
= 4(pi r^2)h
4(pi r^2 = 10 pi r^2 h)
h = (frac{10}{4} = 4.5cm)