Find the ratio ofenergy of a photon of ` 2000Å` wavelength radiation to that of `4000Å` radiation .

Options

A. `(1)/(4)`
B. `4`
C. `2`
D. `(1)/(2)`

Answer

B

Explanation

According to Planck's equation,
`E = (hc)/(lambda)`
Therefore, `E_(1) = (hc)/(lambda_(1))`and `E_(2) = (hc)/(lambda_(2))`
`(E_(1))/(E_(2)) = (hc)/(lambda_(1))xx(lambda_(2))/(hc) = (lambda_(2))/(lambda_(1)) = (4000Å)/(2000Å) = 2`