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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): The ratio for time taken for light emission from an atom to that for release of nuclear energy in fission is 1 : 100.
Reason (R): Time taken for the light emission from an atom is of the order of 10-8s.
✓

Answer

  1. Both A and R are true, and R is the correct explanation of A.

Explanation:

Time taken for the light emission from an atom $\approx10^{-8}\text{s}$

Time taken for release of energy in fission $\approx10^{-6}\text{s}$

$\text{Required ratio}=\frac{10^{-8}}{10^{-6}}=\frac{1}{100}=1 :100$

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