Given below are two statements:
Statement I: Different photosensitive materials respond differently to light, and selenium is more sensitive than zinc or copper.
Statement II: Ultraviolet light causes photoelectric emission from copper, but green or red light does not.
In the light of the above statements, choose the most appropriate answer from the options given below:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Both Statement I and Statement II are correct
Whether a surface gives out photoelectrons depends on two things. These are the material of the surface and the frequency of the light.
Statement I Different photosensitive materials respond differently to light, and selenium is more sensitive than zinc or copper. — True. Each material has its own threshold frequency. Selenium gives photoelectrons more readily than zinc or copper.
Statement II Ultraviolet light causes photoelectric emission from copper, but green or red light does not. — True. Copper has a high threshold frequency. The frequency of ultraviolet light is above it, while green and red light have lower frequencies.
NCERT (2026-27):
Effect of frequency of incident radiation on stopping potential – “Different photosensitive materials respond differently to light. Selenium is more sensitive than zinc or copper. The same photosensitive substance gives different response to light of different wavelengths. For example, ultraviolet light gives rise to photoelectric effect in copper while green or red light does not.”