A mole of red photons of wavelength 725 nm has kJ of energy.

Question

Quizplus · Accepted Answer

The energy of one photon is given by $E=\frac{hc}{\lambda}$ where $h$ is the Planck's constant, $c$ is the speed of light, and $\lambda$ is the wavelength. We need to find the energy of one photon and then multiply it by Avogadro's number to get the energy of one mole of photons. Plugging in the values, we get $E = \frac{(6.626	imes10^{-34})(3	imes10^8)}{725	imes10^{-9}}\approx 2.74	imes10^{-19}$ J. Now, to get the energy of one mole of photons, we multiply it by Avogadro's number: $E_{	ext{mol}}=2.74	imes10^{-19}	imes6.022	imes10^{23}\approx165$ kJ. Therefore, the answer is D.

A Mole of Red Photons of Wavelength 725 Nm Has