Exam-style question
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Which experimental result supports the conclusion that cathode rays are not photons?.
- A.Cathode rays are deflected by magnetic fields.
- B.Cathode rays produce a fluorescent glow.
- C.Cathode rays are unaffected by electric fields.
- D.Cathode rays travel at the speed of light.
Model answer
What a good answer should say
- Cathode rays are deflected by magnetic fields.
Explanation
Why this works
evidence: Photons, being neutral, would not respond to magnetic fields, yet cathode rays bend in such fields. interpretation: The magnetic deflection indicates a charged particle nature.
implication: This observation rules out a photon explanation. conclusion: Deflection by magnetic fields demonstrates cathode rays are charged particles, not photons.
Common mistake
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