Confused About Light & Mass: Get Help Here!

[Dgonzo15]

I just got unit work of light and mass, and know NOTHING about it, and the site has no resource links. Can someone please tell me a general idea of what there is to know about light and mass, formulas, or any resources I can use?

Also, how would you calculate the 'energy' of a photon, such as in the question "A sombrero spontaneously transforms into a light particle. What would be its energy?" ?

 

[mfb]

Books about special relativity should help.

"A sombrero spontaneously transforms into a light particle. What would be its energy?"

It cannot, this would violate energy or momentum conservation. If it transforms into multiple light particles, total energy is conserved. You can calculate the total energy of the sombrero (in its rest frame) with the famous formula E=mc².