Question

An ice cube is floating in water, above which a layer of a lighter oil is poured. As the ice melts completely, the level of water surface (or interface) and upper level of oil will

• A. Rise and fall
• B. Fall and rise
• C. Not change and change
• D. Not change and fall

Answer 1

The correct option is A Rise and fall

As we know that, $\text{mass}=\text{density}\times \text{volume}....\left(1\right)$

As mass of the ice will remain constant before and after melting and density of water is more than that of ice. So, using equation (1) we can say that after melting the part of ice which is inside the water will produce more volume of water than the volume of corresponding ice. Hence, it will increase the level of water.

The density of light oil is less than that of ice. As oil has lower density than ice so, similarly by equation (1) we can say that the part of ice inside oil will produce less volume of water than its actual volume. This'll decrease the level of oil.

Hence, option $\left(\text{A}\right)$ is correct.