Hi Manisha --
I'd suggest you think of this in terms of degrees. It certainly is the case that when a commodity's price goes down there is more demand for it, but the question to ask is "how much more?" You can learn more about this reaction function by checking out this deck on supply and demand [https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=5&ved=0ah…].
Cheers, and thanks for reading!
Will