Question

What is the energy of a photon with a wavelength of 500 nm?
(Use \( c = 3 \times 10^8 \) m/s and \( h = 6.626 \times 10^{-34} \) Js)

• A. \( 4 \times 10^{-19} \) J
• B. \( 2.5 \times 10^{-19} \) J
• C. \( 1.2 \times 10^{-18} \) J
• D. \( 6.6 \times 10^{-19} \) J

Hint:

The energy of a photon is inversely proportional to its wavelength. As the wavelength increases, the energy decreases.

Answer 1

The Correct Option is A

Step 1: Use the formula for the energy of a photon.
The energy of a photon is given by the formula: \[ E = \frac{hc}{\lambda} \] where: - \( h = 6.626 \times 10^{-34} \) Js (Planck’s constant), - \( c = 3 \times 10^8 \) m/s (speed of light), - \( \lambda = 500 \times 10^{-9} \) m (wavelength).
Step 2: Substituting the values.
\[ E = \frac{6.626 \times 10^{-34} \times 3 \times 10^8}{500 \times 10^{-9}} = 4 \times 10^{-19} \, \text{J} \] Conclusion: The energy of the photon is \( 4 \times 10^{-19} \) J.