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Human Eye and Colourful World — Science STD 10 — Question

CBSE BoardEnglish MediumSTD 10ScienceHuman Eye and Colourful World1 Mark
MCQ
For two statements are given $-$ one labelled Assertion $(A)$ and the other labelled Reason $(R)$. Select the correct answer to these questions from the codes $\ce{(a), (b), (c)}$ and $(d)$ as given below :
Assertion : The twinkling of stars is due to the fact that refractive index of the earth's atmosphere fluctuates.
Reason : When light propagates from one medium to another its direction of propagation changes.
  • ✓
    Both $A$ and $R$ are true and $R$ is correct explanation of the assertion.
  • B
    Both $A$ and $R$ are true but $R$ is not the correct explanation of the assertion.
  • C
    $A$ is true but $R$ is false.
  • D
    $A$ is false but $R$ is true.
✓

Answer

Correct option: A.
Both $A$ and $R$ are true and $R$ is correct explanation of the assertion.
The continuously changing atmosphere is able to cause variation in the light coming from a point-sized star because of which the star appears to be twinkling.

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