Question

What is the density of a liquid of mass 10 kg and contained in a cylinder of radius 5 m and surface area (excluding top and bottom) of 10π m^2?

(a) 0.2π kg/m^3

(b) 0.4π kg/m^3

(c) 0.5π kg/m^3

(d) 0.6π kg/m^3

I have been asked this question in examination.

This intriguing question originated from Density in chapter Moles, Density & Concentration of Basic Chemical Engineering

Answer 1

Right choice is (b) 0.4π kg/m^3

The explanation: Height of cylinder = 10π/(2π*5) = 1 m, => volume of cylinder = π(5^2)1 = 25π, => density of liquid = 10/25π = 0.4π kg/m^3.