Question

Calculate the energy of a photon of wavelength 11.56 meters. (Planck’s constant is 6.626 x 10-34 joule seconds; the speed of light is 2.998 x 108 m/s)

Answer 1

v = f.(wavelength)
Because photons travel at the speed of light, v = c = 2.998x10^8m/s
2.998x10^8 = f x 11.56
f = 25934256.06Hz

E = hf = 6.626x10^-34 x 25934256.06
= 1.718403806x10^-26 = 1.718x19^-26 J (3sf)

Answer 2

Answer : The energy of a photon is, $1.718\times 10^{-26}J$

Explanation :

Formula used :

$E=\frac{h\times c}{\lambda}$

where,

E = energy = ?

h = Planck's constant = $6.626\times 10^{-34}Js$

c = speed of light = $2.998\times 10^8m/s$

$\lambda$ = wavelength = 11.56 m

Now put all the given values in the above formula, we get the energy.

$E=\frac{(6.626\times 10^{-34}Js)\times (2.998\times 10^8m/s)}{11.56m}$

$E=1.718\times 10^{-26}J$

Therefore, the energy of a photon is, $1.718\times 10^{-26}J$