InterviewSolution
Saved Bookmarks
InterviewSolution
| 1. |
The wavelength of light in the visible region is about 390 nm for violet colour, about 550 nm (average wavelength ) for yellow - green colour and about 760 nm for red colour . (a ) What are the energies of photons in (ev) at the (i) violet end, (ii) average wavelength , yellow - green colour , and (ii) red end of the visible spectrum ? (Take h = `6.63 xx 10^(-34)` J s and 1 eV= ` 1.6 xx 10^(-19)` J ) , |
|
Answer» Energy of the incident photon, `E= hv = hc//lambda` ` E = (6.63 xx10^(-34) Js) (3 xx 10^(8) m//s)//lambda` ` = ((1.989xx10^(-25))Jm)/lambda ` (i) For violet light , `lambda _(1) = 390 ` nm (lower wavelength end) Incident photon energy , ` E_(1) = (1.989 xx 10^(-25)Jm)/(390xx10^(-9)m)` ` = 5.10xx10^(-19) J = (5.10xx10^(-19)J)/(1.6 xx 10^(-19)J//eV)` = 3.19 eV (ii) For yellow - green light , `lambda_(2) = 550 ` nm (average wavelength ) Incident photon energy , ` E_(2) = (1.989 xx 10^(-25)Jm)/(550 xx10^(-9)m)` ` = 3.62 xx 10^(-19) J = 2.26 eV` (iii) For red light , ` lambda _(3) = 760` nm( higher wavelength end) Incident photon energy ` E_(3) = (1.989 xx 10^(-25)Jm)/(760 xx 10^(-9) m)` ` = 2.62 xx 10^(-19) J = 1.64 eV` |
|