The work function of a substance is 4.0 eV. Then longest wavelength of light that can cause photoelectron emission from this substance approximately
- (A)540 nm
- (B)400 nm
- (C)310 nm✓ Correct
- (D)220 nm
Answer: (C)
Solution
At the threshold the photon energy just equals the work function, , so the longest wavelength that can still eject electrons is m, about nm.
JEE Main · 2004 · 24 Apr 2004 · Offline · Single correct option