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NEETPhysicsDual Nature of Matter

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): If a monochromatic light beam causes photoelectric emission from metal P but not from metal Q , then the threshold wavelength of P must be greater than that of Q . Reason (R): For photoelectric emission to take place, the wavelength of incident light must be less than or equal to the threshold wave

Options

  1. ABoth (A) and (R) are correct but (R) is not the correct explanation of (A)
  2. B(A) is correct but (R) is not correct
  3. CBoth (A) and (R) are correct and (R) is the correct explanation of (A)
  4. D(A) is not correct but (R) is correct

Correct answer

C. Both (A) and (R) are correct and (R) is the correct explanation of (A)

Step-by-step solution

The condition for photoelectric emission is that the incident wavelength ( ) must be less than or equal to the threshold wavelength ( _ th ) of the metal. Thus, Reason (R) is correct. For metal P , emission occurs, so _ th (P) . For metal Q , emission does not occur, so > _ th (Q) . Combining these two inequalities, we get _ th (P) > _ th (Q) , which implies _ th (P) > _ th (Q) . Therefore, Assertion (A) is correct, and Reason (R) provides the exact logical basis to prove it. Both (A) and (R) are correct and (R) is

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