Aman is sitting in the living room doing his homework. His mother opens a bottle of perfume in the corner of the living room. Within a short time, Aman notices the pleasant smell of the perfume even though he is sitting far away from his mother.

(i) Which of the following statements best explains why Aman is able to smell the perfume ?

1. All the particles of the perfume move in one direction.
2. All the particles of the perfume move randomly.
3. All the particles in air move in one direction.
4. None of the above.

(ii) Define diffusion.

(iii) Under which condition will Aman be able to smell the perfume even faster while sitting at the same place ? Justify your answer.

(iv) What is the random movement of parti cles known as ?

(v) We are also able to smell the food from afar while it is being cooked. Is this due to the same reason as in the case of perfume ? Explain.

(i) All the particles of the perfume move randomly.

Reason — Perfume particles mix with air due to their random motion, spreading in all directions until they reach Aman.

(ii) The intermixing of two or more substances due to the motion of their particles in order to get a uniform mixture is called diffusion.

(iii) Aman will smell the perfume faster at a higher temperature. At higher temperature, particles gain more kinetic energy. They move faster, so diffusion happens more quickly.

(iv) Random movement of particles is known as Brownian motion.

(v) Yes, it is due to the same reason (diffusion). The aroma of food spreads through air because food particles evaporate and mix with air. They move randomly and diffuse to reach our nose even from a distance.