A uniform cylindrical log of density 920kg m−3 is placed gently at the interface of two immiscible liquids that do not mix. The upper liquid is oil of density 800kg m−3 and the lower liquid is water of density 1000kg m−3. After equilibrium is reached the log floats partly in oil and partly in water. What percentage of the log’s volume is immersed in the water layer?
a) 40\%
b) 50\%
c) 60\%
d) 70\%