Question

(a) When an incense stick (agarbatti) is lighted in one corner of a room, its fragrance quickly spreads in the entire room. Name the process involved in this.
(b) A girl is cooking some food in the kitchen. The smell of food being cooked soon reaches her brother's room. Explain how the smell could have reached her brother's room.

Answer 1

a)Diffusion of gases

b)Diffusion of gases

Explanation:

a)

• We have incense stick here which is an solid compound which directly converts into the gas state on application of heat.
• This process of direct convesion from one state to the other is called sublimation process.
• So after the conversion , we see that gases diffuse all over the place .
• This random movement all over the place is because they have no force of attraction between the gas particles.
• So gases tend to move in all random directions with infinite degrees of freedom.
• This property of gas is called diffusion of gases.
• This property of gases is called Diffusion of gases which would explain the process abow.

b)

• It is given that a girl is cooking food in kitchen.
• It is common that food has many solid and liquid matters which upon heating gets converted into gases.
• The process of conversion of solids directly into gases is called sublimation of gases.
• So after they get converted into gases they randomoy diffuse into the open air covering all the volume possible.
• This property of gases is called diffusion of gases.
• So this smell carried by the gases reaches different places and hence different people would be able to smell it.

Answer 2

The Property is Diffusion

Explanation:

a.) When an incense stick is burnt, heat cause the vaporization of incense. Due to diffusion, there is rapid movement of vapours, hence reaches us after getting mixed with air. Its we who judge whether the smell is bad/good after sensing it.

b.) Similarly, the hot food after cooking gets mixed with air particles and spreads away from kitchen, thereby reaching us from distances, that too in seconds. There is large space and  high speed between the particles because of the property of fast diffusion of particles in gases. So, we can easily judge that diffusion is the reason of bringing smell to room.