Answer:
Frequency
Step-by-step explanation:
Photons are the packet of energy. They are massless and chargeless particles. They travel in the vacuum with the speed of light. The energy of photon is given by :
![E=h\\u](https://img.qammunity.org/2020/formulas/physics/middle-school/77fy29ydbgip1902b0vgdqn2ucc16ph4u8.png)
Where
h = Planck's constant
= frequency of photon
Or
![E=(hc)/(\lambda)](https://img.qammunity.org/2020/formulas/physics/middle-school/qsv4fkctsmfst9aln3wy2xtnfdwqn1eov2.png)
c = speed of light
= wavelength of photon
From the above equation, it is clear that the energy of photon is directly proportional to its frequency.