We know that when light passes through a black hole it bends. But I couldn't understand why?
As light is composed of photons and we know that photons are massless, we also know that gravity and mass relation, The Real Meaning of E=mc².

How can photons experience gravity? What is making them to bend their path?

What I thought (may be pure nonsense) is due to the nature of spacetime itself, which decides the trajectory around the black hole. Not exactly the mass affected by gravity. This is how I explained it to myself or convinced myself. But I have no background to defend it.

Forgive me, I have no background in GR (General Relativity). If this can be answered more on physical ground without invoking more maths(little or most necessary maths is good).(How to explain this to Ist year undergrad, if he/she ever ask me?)