A firefly glows by the direct conversion of chemical energy to light. Suppose th

Question

A firefly glows by the direct conversion of chemical energy to light. Suppose the light emitted by a firefly has peak intensity at a wavelength of 536 nm. (a) What is the minimum chemical energy, in eV, required to generate each photon? 2.32 Correct: Your answer is correct. eV

(b) One molecule of ATP provides 0.30 eV of energy when it is metabolized in a cell. What is the minimum number of ATP molecules that must be consumed in the reactions that lead to one photon of 536 nm light? 7.73 Incorrect: Your answer is incorrect. ATP molecules

Explanation / Answer

Here wavelenght (w) = 536 * 10^-9 m
we know that, speed of light(c) = ffrequency(f) * w
therefore f = (299792458 / 536 * 10^-9)
f = 5.6 * 10^14 s^-1

also we know that E = plancks constant(h) * f
E = 6.62606957×10^34 * 5.6 * 10^14 s^-1
E = 3.71 * 10^-19 J = 2.32 eV
we know that we require 2.32 eV amount to produce one photon.

0.30 eV of energy is provided by 1 molecule of ATP.
therefore, 2.32 eV is provided by = 2.32/0.3 molecules
=7.73 almost equal to 8 molecules.

My answer also comes same. Here total no. of molecules will be considered 8 not 7.73.

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