Lesson eLearning

A photon of wavelength 0.35 nm is scattered elastically by a stationary electron at an angle of 120°. Find the wavelength of the scattered photon. Which of the following is correct?

medium MCQ 2 marks Class 12 · Physics · Dual Nature of Radiation and Matter
  1. 0.353 nm
  2. 0.347 nm
  3. 0.355 nm
  4. 0.363 nm
Answer
0.353 nm

The correct answer is 0.353 nm — Add to initial wavelength:  nm, rounded to 0.353 nm.

Step-by-step solution

  1. Write Compton shift formula: where  m = 0.002426 nm.
  2. Compute , so .
  3. Calculate  nm.
  4. Add to initial wavelength:  nm, rounded to 0.353 nm.
Common mistake: Using the wrong sign for the cosine term or mixing metres and nanometres in

Concept tested: Compton wavelength shift

Published · How this solution was prepared and checked

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