A uniform cylindrical hydrometer of mass 20g and cross sectional area 0.54cm2 floats upright in a liquid. If 25cm of its length is submerged, calculate the relative density of the liquid. (Density of water = 1 gcm-3)
- 1.54
-
1.48
- 1.25
- 0.80
The correct answer is: B
Explanation
Density of liquid = \(\frac{M}{V}\) = \(\frac{20}{13.5}\) = 1.48g/cm\(^3\)
Volume = area x length = 0.54 x 25 = 13.5cm\(^3\) = volume of cylinder = volume of liquid.
weight of liquid displaced = weight of object = mass of liquid = 20g
volume of liquid = 13.5cm\(^3\)
Relative density of liquid = \(\frac{\text{ density of liquid}}{\text{density of water}}\)
R. d = \(\frac{1.481}{1}\) = 1.48g/cm\(^3\)