Exam-style question
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What does the degree of deflection of cathode rays in magnetic and electric fields indicate about their charge-to-mass ratio?.
- A.It is independent of the charge.
- B.It is directly proportional to the charge.
- C.It is inversely proportional to the mass.
- D.It is affected by the speed of the rays.
Model answer
What a good answer should say
- It is inversely proportional to the mass.
Explanation
Why this works
The evidence from the deflection of cathode rays indicates that the extent of deflection is greater for lighter particles. This shows that the charge-to-mass ratio is inversely proportional to the mass of the particles.
Therefore, the implication is that lighter charged particles will deflect more than heavier ones, leading to the conclusion that the charge-to-mass ratio is a critical factor in understanding cathode rays.
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