So, there are really 2 parts to this question:
1: How did ESTOR lead to reconceptualization of theory of light
Think About:
- Define Einstein's ESTOR in terms of his 2 postulates
- Speed of light before being relative and distance/time being absolute (Newtonian)
- Speed of light after being constant and distance/time being relative
2. How did his explanation of PE Effect lead to reconceptualization
Think About:
- Describe PE Effect
- Theory of light before being waves (Unable to explain threshold frequency, why intensity does not impact Ek of emitted electrons etc..)
- Theory of light after as light having particle properties, then energy of which is defined by E=hf (explains existence of threshold frequency and why intensity of light has no impact of Ek of electrons etc..)
Then just make a concluding statement showing the model before and after and how ESTOR and his explanation of PE Effect caused changes in the model