The energy $E$ of a photon can be calculated using the equation:

$E = h \cdot f$

where:

• $E$ is the energy of the photon,
• $h$ is Planck's constant ($6.626 \times 10^{-34} \, \text{J·s}$),
• $f$ is the frequency of the photon.

Given:

• $f = 6.91 \times 10^{15} \, \text{Hz}$

Substituting the values into the equation:

$E = (6.626 \times 10^{-34} \, \text{J·s}) \cdot (6.91 \times 10^{15} \, \text{Hz})$

Let's calculate it:

$E = 4.579 \times 10^{-18} \, \text{J}$

So, the energy of the photon is approximately $4.579 \times 10^{-18} \, \text{J}$.

Would you like more details or have any questions?

Here are five related questions you could explore:

1. What is the relationship between wavelength and frequency in light?
2. How does photon energy relate to the color of visible light?
3. What is the wavelength of a photon with the given frequency?
4. How is the photoelectric effect related to photon energy?
5. How does photon energy change with frequency?

Tip: Higher frequency photons, like X-rays and gamma rays, carry more energy than lower frequency photons, such as visible light or radio waves.