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* 10^(-26)J`

Explanation :

Formula used :

`E=(h* c)/(\lambda)`

where,

E = energy = ?

h = Planck's constant =
`6.626* 10^(-34)Js`

c = speed of light =
`2.998* 10^8m/s`

`\lambda` = wavelength = 11.56 m

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

`E=((6.626* 10^(-34)Js)* (2.998* 10^8m/s))/(11.56m)`

`E=1.718* 10^(-26)J`

Therefore, the energy of a photon is,
`1.718* 10^(-26)J`