Which of the following scientists has not contributed significantly to photoelectric effect?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → C.J. Davisson
Three of the names are linked with the discovery and explanation of the photoelectric effect:
Wilhelm Hallwachs showed in 1888 that a zinc plate lost its charge when ultraviolet light fell on it.
Philipp Lenard studied the emission of electrons by ultraviolet light from a metal plate in an evacuated tube, and found that there is a threshold frequency.
Albert Einstein explained the effect in 1905 with the photon picture, \( K_{\max} = h\nu - \phi_0 \).
C.J. Davisson is known for the Davisson–Germer experiment (1927), in which electrons were diffracted by a nickel crystal. That experiment confirmed the wave nature of electrons proposed by de Broglie and has nothing to do with the photoelectric effect.
NCERT (2026-27):
Hallwachs’ and Lenard’s Observations – “Wilhelm Hallwachs and Philipp Lenard investigated the phenomenon of photoelectric emission in detail during 1886-1902.”
Einstein’s Photoelectric Equation: Energy Quantum of Radiation – “In 1905, Albert Einstein (1879-1955) proposed a radically new picture of electromagnetic radiation to explain photoelectric effect.”