Question

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

Plz help me with correct and complete solution!



Physical science question
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Answer 1

2.012 * 10^16

Explanation:

Energy of one photon (E) = hv

Energy of ‘n’ photons (En) = nhv => n = Enλ/hc

Where λ is the wavelength of the photons:

= 4000 pm = 4000 * 10^-12 meter

c denotes the speed of light in vacuum = 3 * 10^8 m/sec

h is plancks constant whose value = 6.26 * 10^-34 j/sec

Substituting these values in the expression for n:

n = 1 * 4000 * 10^-12 /( 6.26 * 10^-34)(3*10^5)

= 2.012 * 10^16

Hence, the number of photons with a wavelength of 4000 pm and energy of 1 J are 2.012 * 10^16.