Question

the small of lighted incense stick reaches several meters away but to get the smell from unlighted incense stick you have to go lose

Answer 1

Lightened incense stick's smell reaches us by the process of diffusion and diffusion is faster in high temperature but unlighted incense stick has no high temperature

Answer 2

When molecules of some volatile substances from hot sizzling food diffuse into air and reach the odur sensitive part of our nose we have the perception of smell.

At higher temperature of molecules diffuse into air at a faster rate and therefore travel long distances.

Hence the smell of hot sizzling food reaches as quickly even when we are several metres away.

While on the contrary , when the food is called the vapour diffuse is at a slower rate and therefore does not travel longer distances.

So, one has to come closer to have the perception of smell.