Question

Among the following, number of metal/s which can be used as electrodes in the photoelectric cell is ________ . (Integer answer)
(A) Li (B) Na (C) Rb (D) Cs

Hint:

Metals suitable for photoelectric cells are those with low work functions. The alkali metals are the prime examples, with work functions decreasing as you go down the group. Cesium is the most commonly used due to having one of the lowest work functions.

Answer 1

Correct Answer: 1

Q58. Metals given: Li, Na, Rb, Cs. Concept: Photoelectric cells require metals with low work function. Observation: All alkali metals have low work functions and can emit electrons under visible light. Conclusion: \[ \boxed{4} \]