atomic structure

I suppose that you have read O.P. Tandon's book for physical chemistry.In that book it is given that it is for mass.Mass can be converted into energy.
So this equation E=mc² is only for mass.How are you using it for photons?Is photon disappearing?Tandonji says that this equation is valid when the mass is disappearing.Please read this book.It is quite interesting.I think that this book can tell more than me.

In classical mechanics , a particle must hav rest mass in order to hav energy and momentum, but relativistic mechanics this requirement doesn't hold..
when v=c and m=0, E=0/0,p=0/0, which are indeterminate: E and p can hav any values.

E^{2}=(mc^{2})^{2}+p^{2}c^{2}. This equation gives us the relationship between E and p for a massless particle with m=0:

E=pc

Amit
From which equation are you getting E=0/0.
I think you have p as momentum
P=mc=o*v=0
Where is p=0/0.
I think you are using such equations which are not in our iitjee syllabus.
And there is one more also
E²=(mc²)²+p²c²
What have you done?Which book did you see in?Are you some college level student?Then what is the use of this equation here?
If you have seen this equation anywhere would you like to show me its proof?This equation is out of our jee syllabus.