Question

mculane
Q: 7 The wavelength of a beam of light is 250 um. What is: (i) Its
wavelength in cm
(in Its frequency (11) Its wave number (iv) Energy of its one
proton.​

Answer 1

Explanation:

1. one um is 10^-4 cm wavelength is 25×10^-3 cm or 250×10^-4 cm
2. speed of light is 3× 10^8 m/s frequency is equal to speed /wavelength hence frequency of light is( 3×10^8m/s)/(25 ×10^-5m ) =12×10^11 /s or 12×10^11 Hertz
3. wave number is the reciprocal of wavelength hence wavenumber = 1/(25×10^-5)=4000 /m
4. energy of one photon is equal to plank's constant × frequency =(6.6×10^-34)×(12×10^11)=7.92×10^-22 Joule or 4.325 ×10^-3 electron volt.

I hope so I answered the question correctly.