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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): When monochromatic light of wavelength 620 nm at very high intensity falls on a metal surface having a work function of 2.5 eV, the photoelectric current remains zero. Reason (R): The energy of a single photon of 620 nm is less than the work function of the metal, and photoelectric emission is a on

Options

  1. ABoth Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A)
  2. BBoth Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A)
  3. CAssertion (A) is true but Reason (R) is false
  4. DAssertion (A) is false but Reason (R) is true

Correct answer

A. Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A)

Step-by-step solution

The energy of an incident photon is calculated as E = hc . Substituting the given values: E = 1240 eV nm 620 nm = 2.0 eV . The work function of the metal is = 2.5 eV . Since the energy of the incident photon ( 2.0 eV) is strictly less than the work function ( 2.5 eV), a single photon does not possess enough energy to eject an electron from the metal surface. Photoelectric emission is a quantum phenomenon where one electron absorbs exactly one photon. Because of this one-to-one interaction, increasing the intensity

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