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12. atoms — Physics STD 12 Science — Question

CBSE BoardEnglish MediumSTD 12 SciencePhysics12. atoms1 Mark
MCQ
Assertion : Soft and hard $X-$ rays differ in frequency as well as velocity.
Reason : The penetrating power of hard $X-$ rays is more than the penetrating power of soft $X-$ rays.
  • A
    If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion.
  • B
    If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.
  • C
    If the Assertion is correct but Reason is incorrect.
  • ✓
    If both the Assertion and Reason are incorrect.
✓

Answer

Correct option: D.
If both the Assertion and Reason are incorrect.
d
Soft and hard $X-$ rays differ only in frequency. Soft $X-$ rays have low frequency as compared to hard $X-$ rays. But both types of  $X-$ ray travel with speed of light.

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