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.
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? [email protected]
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.
Practise Dawn of Modern Physics
739 free Dawn of Modern Physics MCQs from Physics, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Discussion
Stuck on an option, or know a faster way to get there? Ask or explain it here.
No comments yet. Be the first to explain this one.
Exams that ask Physics questions like this
Physics is on 16 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
More Dawn of Modern Physics questions
The special theory of relativity is based upon:(I) the laws of physics are the same in all inertial frames.(II) The speed of light in free space has the same value for all observers regardless of their state of motion.
Which of the following physical phenomena connot be described only by the wave theory of the electromagnetic radiation?
Which radiation passes through black body:
The threshold frequency for the photoelectric effect on sodium corresponds to a wavelength of 5000x10-10. Its work function is:
A photon behaves as if it had a mass equal to:
A cesium photocell, with a steady potential difference of 60V across it, is illuminated by a small bright light placed 1 m away. When the same light is placed 2m away, the number of electrons crossing the photocell: