Question

calculate the energy of photon of red light having wavelength 650 nm

Answer 1

HELLO THERE!

From Plank's Quantum Theory, we know that:

E = hν, where h is Plank's Constant and ν is Frequency of the photon.

Now, c = νλ (where c = Speed of light in air)

From here, we can get ν = c/λ

Put this in the above equation, we get:

$E = \frac{hc}{\lambda} \\\\\implies E = \frac{6.626\times10^{-34} \times 3\times10^{8}}{650\times10^{-9}} \\\\\implies E = 3.058\times10^{-19}J$

Note:

Plank's constant h = 6.626 x 10⁻³⁴ Js.

Wavelength = 650 nm = 650 x 10⁻⁹ m.

c (Speed of light in air) = 3 x 10⁸ m s⁻¹

THANKS!