A photon of wavelength 490 nm behaves like a particle of a certain mass. The value of that mass is

JAMB Physics 2023 324 views
Source: JAMB · 2023

A photon of wavelength 490 nm behaves like a particle of a certain mass. The value of that mass is

[h = 6.63 x 10-34 Js, c = 3 x 108 ms-1]

A photon of wavelength 490 nm behaves like a particle of a certain mass. The value of that mass is

[h = 6.63 x 10-34 Js, c = 3 x 108 ms-1]

  1. 1.2 x 10-36 kg
  2. 4.5 x 10-36 kg ✓
  3. 3.6 x 10-36 kg
  4. 2.8 x 10-36 kg
Explanation

A photon’s energy is E = hc/λ. Using E = mc², the equivalent mass is m = h/(λc).

m = 6.63 × 10⁻³⁴ ÷ (490 × 10⁻⁹ × 3 × 10⁸) = 6.63 × 10⁻³⁴ ÷ 147 ≈ 4.5 × 10⁻³⁶ kg.

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