Question

A photon has an energy of 5.53 x 10^-17 Joules when the frequency is 8.34 X 10^16 Hz. What will happen to the energy of the photon if the frequency is decreased to 2.79 X 10^8 Hz? Note: 8, 16, & 17 are exponents.

A) The energy will decrease.
B) The energy will increase.
C) The energy will remain the same.
D) The energy will increase and then decrease dramatically.

Answer 1

The energy of a photon will decrease if its frequency is decreased, due to the direct proportionality between energy and frequency represented by Planck's equation (E = hf).

Step-by-step explanation:

When the frequency of a photon decreases, its energy also decreases. This is based on the fundamental relationship between energy (E) and frequency (f) given by Planck's equation, E = hf, where h is Planck's constant. If we have a photon with a decreased frequency from 8.34 x 1016 Hz to 2.79 x 108 Hz, this reduction in frequency will result in a proportional decrease in the photon's energy. This can be understood through examples given in the check your learning sections where we see that energy and frequency are directly proportional (e.g., for a photon with frequency 5.5 x 1014 Hz, the energy is calculated to be 3.6 x 10-19 J).