Modern Physics 1 Question 49

45. Wavelengths belonging to Balmer series lying in the range of 450nm to 750nm were used to eject photoelectrons from a metal surface whose work function is 2.0eV. Find (in eV) the maximum kinetic energy of the emitted photoelectrons. (Take hc=1242eVnm.

(2004,4 M)

Show Answer

Solution:

  1. Wavelengths corresponding to minimum wavelength (λmin) or maximum energy will emit photoelectrons having maximum kinetic energy. (λmin ) belonging to Balmer series and lying in the given range (450nm to 750nm ) corresponds to transition from (n=4 to n=2). Here,

E4=13.6(4)2=0.85eV and E2=13.6(2)2=3.4eVΔE=E4E2=2.55eVKmax= Energy of photon  work function =2.552.0=0.55eV



जेईई के लिए मॉक टेस्ट

एनसीईआरटी अध्याय वीडियो समाधान

दोहरा फलक