A photon has 8. 0 × 10–15 J of energy. Planck’s constant is 6. 63 × 10–34 J•s. What is the frequency of the photon? 1. 21 × 1019 Hz 8. 3 × 10–20 Hz 1. 21 × 10–19 Hz 8. 3 × 1020 Hz.