Verified Solution • 2025–26 Session moderate

QJEEM22Ch8778: JEE Main 2022 Chemistry - Class 11 JEEM22Ch8778 Solution: The energy of one mole of photons of radiation of wavelength…

The energy of one mole of photons of radiation of wavelength 300 nm is

(Given : h = 6.63 ×\times 10 −- 34 J s, NA = 6.02 ×\times 1023 mol −- 1, c = 3 ×\times 108 m s −- 1)

Multiple Choice Options

  • A 235 kJ mol −- 1
  • B 325 kJ mol −- 1
  • C 399 kJ mol −- 1
  • D 435 kJ mol −- 1

Step-by-Step Verified Solution

Energy of one photon

E=1240λ(nm)eVE = {{1240} \over {\lambda (nm)}}eV

=1240300= {{1240} \over {300}}

=4.1333 eV= 4.1333\,eV

∴\therefore Energy of one mole of photon

=4.1333×6.02×1023 eV= 4.1333 \times 6.02 \times {10^{23}}\,eV

=4.1333×6.02×1023×1.6×10−19 J= 4.1333 \times 6.02 \times {10^{23}} \times 1.6 \times {10^{ - 19}}\,J

=4.1333×6.02×1023×1.6×10−191000 kJ= {{4.1333 \times 6.02 \times {{10}^{23}} \times 1.6 \times {{10}^{ - 19}}} \over {1000}}\,kJ

=399 kJ/mol= 399\,kJ/mol

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