Answer:
7.51 × 10¹⁷
Step-by-step explanation:
1. Calculate the energy of one photon
The formula for the energy of a photon is
E = hc/λ
h = 6.626 × 10⁻³⁴ J·s; c = 2.998 × 10⁸ m·s⁻¹
λ = 531 nm = 531 × 10⁻⁹ m Insert the values
E = (6.626 × 10⁻³⁴ × 2.998× 10⁸)/(531 × 10⁻⁹)
E = 3.741× 10⁻¹⁹ J
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2. Calculate the number of photons
Divide the total energy by the energy of one photon.
No. of photons = 0.281 × 1/3.741 × 10⁻¹⁹
No. of photons = 7.51 × 10¹⁷ photons