Introduction to Photon Energy Calculation

The energy of photon 600 nm wavelength is a key concept in quantum physics for CSIR NET Life Sciences and Physics exams. Green light at 600 nm carries photon energy of 2.1 eV, derived from Einstein’s equation E = hc / λ. This calculation uses given constants: Planck’s constant = 6.63 × 10⁻³⁴ Js, speed of light = 3 × 10⁸ m/s, and 1 eV = 1.6 × 10⁻¹⁹ J.

Step-by-Step Calculation

Convert wavelength to meters: λ = 600 nm = 600 × 10⁻⁹ m = 6 × 10⁻⁷ m.

Photon energy formula: E = hc / λ, where h = 6.63 × 10⁻³⁴ J s, c = 3 × 10⁸ m/s.

First, compute numerator: hc = (6.63 × 10⁻³⁴) × (3 × 10⁸) = 1.989 × 10⁻²⁵ J m.

E = 1.989 × 10⁻²⁵ / 6 × 10⁻⁷ = 3.315 × 10⁻¹⁹ J

Convert to eV: E_eV = 3.315 × 10⁻¹⁹ / 1.6 × 10⁻¹⁹ = 2.1 eV (rounded to one decimal).

Detailed Solution for CSIR NET Q.44

Start with λ = 600 × 10⁻⁹ m. Compute E = (6.63 × 10⁻³⁴) × (3 × 10⁸) / 600 × 10⁻⁹ = 3.315 × 10⁻¹⁹ J.

Divide by eV conversion: 3.315 × 10⁻¹⁹ ÷ 1.6 × 10⁻¹⁹ = 2.071875 ≈ 2.1 eV. Matches sources confirming ~2.07-2.1 eV for 600 nm.

Common Exam Traps

• Forgetting nm to m conversion yields wrong order (~10⁻¹⁷ J).
• Using h = 6.626 × 10⁻³⁴ gives minor variance (still 2.1 eV).
• Inverse error (λ in denominator) or c = 3 × 10¹⁷ nm/s leads to ~3.3 eV (red light mismatch).
• Unrounded: 2.07 eV, but question specifies one decimal: 2.1 eV.

Applications in Life Sciences

In photosynthesis, 600 nm photons (~2.1 eV) excite chlorophyll electrons for energy transfer. CSIR NET questions test this in photobiology and quantum biology sections.

Quick Formula Tip

Memorize hc ≈ 1240 eV nm: E ≈ 1240 / 600 = 2.07 eV. Ideal for exam speed.