Question

The energy of photon is given by: ____.

• A. E = mc²
• B. \( E = h\nu \)
• C. E = F/q
• D. E = qV

Hint:

Higher frequency light (like Blue or UV) has more energy per photon than lower frequency light (like Red or Infrared). This is why UV light can cause sunburns while visible light cannot!

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
In quantum mechanics, light is treated as a stream of particles called photons. The energy of an individual photon is proportional to its electromagnetic frequency.

Step 2: Key Formula or Approach:
The energy ($E$) of a photon is given by the Planck-Einstein relation: \[ E = h\nu \]

Step 3: Detailed Explanation:

• $E$: Energy of the photon.
• $h$: Planck's constant ($6.626 \times 10^{-34}$ J·s).
• $\nu$ (nu): The frequency of the light. Note: Since $\nu = c/\lambda$, the energy can also be written as $E = hc/\lambda$. Option (A) $E=mc^2$ is Einstein's mass-energy equivalence, and (D) $E=qV$ is the work done on a charge in an electric field.

Step 4: Final Answer:
The energy of a photon is $E = h\nu$.