question_answer 27)

What is the number of photons of light with a wavelength of 4000 pm that provide 1 J of energy?

Answer:

Let x quanta of radiation provide 1 J of energy \[E=xh\frac{c}{\lambda }\] \[1=\frac{x\times 6.626\times {{10}^{-34}}\times 3\times {{10}^{8}}}{4000\times {{10}^{-12}}}\] On solving \[x=2.012\times {{10}^{16}}\] quanta