Question

The energy of a photon of radiation of wavelength 4000 angstrom is 'E'. Then the wavelength of a photon of light having energy equal to '2E' will be:

Answer 1

Explanation:

Answer: 8000 angostrom

Explanation: here is the easiest way

We know that,

Energy of a photon,

E = hc/λ

here h and c are constants

Therefore E is inversely proportional by λ

Therefore, if anergy is halves to make it 0.5E,

Wavelength is doubled

Hence new wavelength, λ' = 2λ = 2 x 4000 angostrom

>> λ' = 8000 angostrom