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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): The minimum wavelength of continuous X-rays produced in an X-ray tube increases when the accelerating voltage is increased. Reason (R): The minimum wavelength corresponds to the case where the entire kinetic energy of an incident electron, which is directly proportional to the accelerating voltage,

Options

  1. ABoth (A) and (R) are true and (R) is the correct explanation of (A).
  2. BBoth (A) and (R) are true but (R) is not the correct explanation of (A).
  3. C(A) is true but (R) is false.
  4. D(A) is false but (R) is true.

Correct answer

D. (A) is false but (R) is true.

Step-by-step solution

The minimum wavelength (cutoff wavelength) of continuous X-rays is given by _ min = hc eV . This relation shows that _ min is inversely proportional to the accelerating voltage V . Therefore, when the accelerating voltage is increased, the minimum wavelength decreases. Thus, Assertion (A) is false. Reason (R) is true because the cutoff wavelength is produced when an incident electron loses its entire kinetic energy ( K = eV ) in a single collision, emitting a single photon of maximum energy E_ max = hc _ min . The

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