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Dual Nature of Radiation and Matter — Physics STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 SciencePhysicsDual Nature of Radiation and Matter1 Mark
Question
For question two statements are given-one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer to these questions front 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): Some photographic plates are not affected by red light but are immediately blackened by white light.
Reason (R): The wavelength of red light is less than the wavelength of many components of white light.
✓

Answer

  1. A is true but R is false.
Explanation:

The energy of red light photon is less than the work function of photographic plate, while the energies of many components of white light such as blue, violet etc are more than the work function of photographic plate. lnfact different photographic plates are used for different regions of spectra.

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