TG EAMCET 4 May 2025 Shift 1 Paper

According to the question, given values are
Planck's constant, h=6.63×10−34Js
NA=6×1023mol−1
Wavelength,
λ=331.5nm=331.5×10−9m
Kinetic energy (per mole)
=1.2×105J∕mol
The energy of a single photon is given by the formula, E=‌

hc

λ

Substituting the given values,
E‌=‌

6.63×10−34×3×108

331.5×10−9

‌=6.00×10−19J
Energy per mole of photons,
E‌mol ‌‌=6.00×10−19×6×1023
‌=3.6×105J∕mol
Using photoelectric equation (per mole)
Work function (mol)=E‌mol ‌−KE
=3.6×10−5−1.2×105

=2.4×105J∕mol
Since, 1eV=96,485J∕mol
φ=‌

2.4×105

96485

≈2.5eV