Answer:
2.65 × 10^-19 J
Step-by-step explanation:
The energy of a photon of light of this wavelength can be calculated using;
E = hf
Where; E = Energy of photon (J)
h = Planck's constant (6.626 × 10^-34 Js)
f = frequency of photon
However, to get the frequency of the photon (f), we use:
f = c/λ
λ = wavelength = 750nm = 750 × 10^-9m
c = speed of light = 3 × 10^8m/s
f = frequency
f = 3 × 10^8/750 × 10^-9
f = 0.004 × 10^(8+9)
f = 0.004 × 10^17
f = 4 × 10^14 Hz
Since f = 4 × 10^14 Hz, h = 6.626 × 10^-34 Js
E = hf
E = 6.626 × 10^-34 × 4 × 10^14
E = 26.504 × 10^-20
E = 2.65 × 10^-19 J