Physics
In evaporation:
- all molecules of liquid begin to escape out
- only the molecules at the surface escape out
- the temperature of liquid rises by absorbing heat from surroundings
- the molecules get attracted within the liquid
Answer
only the molecules at the surface escape out
Reason — In evaporation, some molecules near the surface of liquid acquire sufficient kinetic energy by collisions with the other molecules, to reach the surface. These molecules absorb heat from the surroundings to escape out in space.
Related Questions
The rate of evaporation of a liquid increases when:
- temperature of liquid falls
- liquid is poured in a vessel of less surface area
- air is blown above the surface of liquid
- humidity increases
During boiling or vaporization:
- all molecules take part
- temperature rises
- no heat is absorbed
- the average kinetic energy of molecules increases
The boiling point of a liquid is increased by:
- increasing the volume of liquid
- increasing the pressure on liquid
- adding ice to the liquid
- decreasing pressure on liquid
Two rods A and B of the same metal, but of length 1 m and 2 m respectively, are heated from 0°C to 100°C. Then:
- both the rods A and B elongate the same
- the rod A elongates more than the rod B
- the rod B elongates more than the rod A
- the rod A elongates, but the rod B contracts