AIIMS 2018 Physics Threshold Frequency Assertion Reason Question

Threshold frequency ($f_0$) is the minimum frequency of incident light required to eject electrons from a material's surface, which indeed varies depending on the type of metal due to differences in work function ($ϕ$). Thus, the assertion that threshold frequency depends on the material is true. However, the reason provided, which may imply that threshold frequency is solely determined by factors unrelated to the material properties, is false. Other options may incorrectly assert that both statements are true or that the assertion is false, which misrepresents the relationship between threshold frequency and material properties. Understanding this distinction is crucial for grasping the photoelectric effect and the role of material characteristics in electron emission.