Question

identify the factor that make sound soft or loud ? give one example foe each ?

Answer 1

Whether the sound is soft or loud is decided by the amplitude of the sound wave. 

To further clear this, I'd like to explain you what amplitude is? :)

Amplitude is the maximum displacement made by a wave from its mean position to its extreme position.  It's basically the maximum displacement made.

So, How does it effect the loudness of a sound?

The greater the amplitude is, the louder the sound becomes. So, If the measure of amplitude (maximum displacement) is large, the sound will be the loud. And if the amplitude is less, the sound will be soft.

For. e.g- A bird's sound is soft whereas lion's roar is loud, this is because the amplitude differs in both of them. 

I hope, it is clear to you now? :)