Subject Experts Solutions for Chapter: Heat, Exercise 2: PRACTICE QUESTIONS (COMPETITION WING)

$20 \mathrm{g}$ of water at $50°\mathrm{C}$ is mixed with $10 \mathrm{g}$ of water at $15°\mathrm{C}$, then find the equilibrium temperature of the mixture.

Explain why a clinical thermometer is exclusively used to measure the human body temperature and a laboratory thermometer is used to measure the temperatures of different substances but not to measure the human body temperature.

Two beakers A and B contain water at different temperatures. When $1 \mathrm{litre}$ of water from beaker A is mixed with$2 \mathrm{litre}$ of water from beaker B, the equilibrium temperature is $16°\mathrm{C}$ and when $2 \mathrm{litre}$ of water from beaker A is mixed with $2 \mathrm{litre}$ of water from beaker B, then the equilibrium temperature is $14°\mathrm{C}$. Determine the temperature of water in the beakers A and B.

Two beakers contain hot water of the same temperature. One beaker is placed in another beaker containing cold water and the other beaker in front of a rotating fan. It is observed that the beaker placed in front the fan cools faster. Explain the reason.

When the same amount of heat is supplied to the different materials, will they increase their temperature by the equal amount? Why?

A test tube is filled with some water. A small piece of wax is fixed at the bottom of the test tube and a small piece of wax is made to float on the water. What happens to the wax at the top and bottom of the test tube if the test tube is heated at the top, middle and bottom?

Why is hot water more effective than cold water in extinguishing fire?

Rajini is heating her metal scale of length 15 cm; she found that the length of the metal scale is increased by $\text{1 cm}$. Then find the length of a single division on the scale after heating and find the difference between the smallest division before and after heating the scale.