Question

A liquid is exposed to infrared radiation with a wavelength of 4.63 x 10-4 cm. Assume that all the radiation is absorbed and converted to heat. How many photons are required for the liquid to absorb 10.77 J of heat? number of photons =

Answer 1

Use formula for energy of a photon as follows Energy of 1 photon = hc/ λ

here, h= 6.626 x10^-34 js, c = speed of light = 3 x10^8 m/s, and λ = 4.63×10−4 cm = 4.63×10−6 m

E =6.626 x10^-34 js* 3 x10^8 m/s/ 4.63×10^−6 m
E = 4.2933 x10^-20 J

Energy of 1 photon = 4.2933 x10^-20 J

Number of photons needed = 10.77 J/ 4.2933 x10^-20 J
Number of photons = 2.5085 x10^20 photons

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