Question

Which among the following photons will have highest wavelength?
{h = 6.6 × 10^-34 J-s, C = 3 × 10⁸ m/s}

• A. 10 J Energy Photon
• B. 100 J Energy Photon
• C. 1000 J Energy Photon
• D. 10000 J Energy Photon

Hint:

Energy and Wavelength are like a see-saw: when one goes up, the other goes down. High Energy = Short Wavelength (Blue/UV); Low Energy = Long Wavelength (Red/Infrared).

Answer 1

The Correct Option is A

Concept: The energy of a photon ($E$) is inversely proportional to its wavelength ($\lambda$). This relationship is defined by Planck's equation: \[ E = \frac{hc}{\lambda} \quad \text{or} \quad \lambda = \frac{hc}{E} \] where $h$ is Planck's constant and $c$ is the speed of light.

Step 1: Analyzing the Inverse Relationship.
From the formula $\lambda \propto \frac{1}{E}$, it is clear that as the energy of the photon increases, its wavelength decreases. Conversely, as the energy decreases, the wavelength increases.

Step 2: Comparing the given values.
To find the highest wavelength, we must identify the photon with the lowest energy.
• Option 1: 10 J (Lowest Energy)
• Option 4: 10000 J (Highest Energy) The 10 J photon will have the largest (highest) wavelength among the choices.