B Do photons have mass and how does it affect their existence?

[superkraken]

this is the first time I am learning about photons and i have asmall doubt.
if photons are massless then how come light dosent escape from black holes.
or if they do have mass the by the eqn m=m0/(1-V²/c²)then theyll have infinite mass and turning on a torch may be like getting hit by a bullet train.so how do photons actually exist.with mass or without it?

 

[Drakkith]

if photons are massless then how come light dosent escape from black holes.

Because they still exist in spacetime and thus have to follow the appropriate paths through spacetime. A black hole bends spacetime in such a way that ALL paths through spacetime lead further into the black hole.

That's a bare minimum explanation, and if you want to know more I encourage you to look into relativity.

so how do photons actually exist.with mass or without it?

They have no mass, but they still have energy and momentum. Einstein's full equation is: e² = m²c⁴ + p²c²

The term which includes mass is zero for photons, but the second is not, and reduces to: e=pc

 

[dextercioby]

this is the first time I am learning about photons and i have asmall doubt.
if photons are massless then how come light dosent escape from black holes.
or if they do have mass the by the eqn m=m0/(1-V²/c²)then theyll have infinite mass and turning on a torch may be like getting hit by a bullet train.so how do photons actually exist.with mass or without it?

Photons are quantum objects, elementary lumps of energy of the electromagnetic field. As of such, they have a hard time sharing classical particle properties (like position). If one still adopts a quantum particle interpretation of the uni-photon states, then these objects are massless, i.e. zero invariant mass.
When one forcibly puts photons in black holes, they do escape, as far as I know.

 

[weirdoguy]

You may want to read this:
https://www.physicsforums.com/insights/do-photons-have-mass/

by the eqn m=m0/(1-V2/c2)

and this:
https://www.physicsforums.com/insights/what-is-relativistic-mass-and-why-it-is-not-used-much/