Light contains two frequencies: ω1=3×1015 rad/s and ω2=12×1015 rad/s
For maximum KE, use higher frequency ω2.
Energy: E2=2πhω2=2π6.6×10−34×12×1015
=6.2879.2×10−19=12.6×10−19 J =7.9 eV
KEmax=E2−ϕ=7.9−2.8=5.1 eV
A light wave described by E=60 [sin (3 × 10^15 ) t+sin (12 × 10^15 ) t ] (in SI units) falls on a metal surface of work function 2.8 eV. The maximum…
JEE Main 2026 — Physics Modern Physics
2026mcqmedium
A light wave described by E=60[sin(3×1015)t+sin(12×1015)t] (in SI units) falls on a metal surface of work function 2.8 eV. The maximum kinetic energy of ejected photoelectron is (approximately) ____ eV. (h=6.6×10−34 J. s. and e=1.6×10−19C)
Official previous-year question
Held on 21 Jan 2026 · Verified 6 Jul 2026.
Options
- A
7.8
- B
6.0
- C
5.1
- D
3.8
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