Fluorescence is produced when cathode rays strike on:
Correct answer: D. ZnS
- A. Fe
- B. MgO
- C. I
- D. ZnS
Explanation
When cathode rays strike ZnS (zinc sulfide), it emits a green glow. When zinc sulfide gets hit by electrons of the cathode rays, electrons transfer some of their energy to zinc sulfide and excite its electrons. Zinc sulfide stores the energy for a while and then emits light when the electron goes back to its ground level. This causes fluorescence and a green glow.
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About Dawn of Modern Physics
Classical physics cannot explain blackbody radiation and related observations, leading to Planck’s quantum theory, in which energy is emitted or absorbed in discrete packets. Photons provide the particle model of light, with energy and momentum linked to frequency and wavelength, including the photoelectric effect and its threshold frequency.
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