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Nuclei — Physics STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 SciencePhysicsNuclei1 Mark
Question
For question, statements are given-one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer to these questions from the codes (a) (b) (c) and (d) as given below.
  1. Both A and R are true, and R is the correct explanation of A.
  2. Both A and R are true, but R is NOT the correct explanation of A.
  3. A is true, but R is false.
  4. A is false and R is also false.
Assertion (A): Rydberg's constant varies with the mass number of a given element.
Reason (R): The reduced mass of the electron depends on the mass of the nucleus only.
✓

Answer

  1. A is false and R is also false.
Explanation:

The Rydberg constant is given by $\text{R}=\frac{13.6\text{eV}}{\text{hc}}$

Which is independent of the mass number of an element. Reduced mass of the system depends on the masses of both the electron as well as nucleus.

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