In astronomical observations, signals observed from the distant stars are generally weak. If the photon detector receives a total of 3.15 × 10 –18 J from the radiations of 600 nm, calculate the number of photons received by the detector.

Question

Philoid · Accepted Answer

Given:

Energy, E = 3.15 × 10^–18 J

Wavelength, λ = 600 nm

By Planck’s relation we have,

Energy, E = h×v

But we know v = [c] / [λ]

Where

c = Speed of Light

v= Frequency

λ = Wavelength

So, E = hc /λ

= [[6.626×10^-34] × [3×10⁸]] / [600×10^-9]

= [1.9878×10^-25] / [600×10^-9]

= 3.313×10^-19 J

Therefore, number of photons received = [3.15 × 10^–18] / [3.313×10^-19]

= 9.5

Therefore, the number of photons received cannot be in fraction

So, number of photons received is 9.

In astronomical observations, signals observed from the distant stars are generally weak. If the photon detector receives a total of 3.15 × 10–18 J from the radiations of 600 nm, calculate the number of photons received by the detector.

In astronomical observations, signals observed from the distant stars are generally weak. If the photon detector receives a total of 3.15 × 10^–18 J from the radiations of 600 nm, calculate the number of photons received by the detector.