question_answer 14)

Given below are some famous numbersassociated with electromagnetic radiationsin different contexts in physics State the partof the electromagnetic spectrum to whicheach belongs. (a) 21 cm (wavelength emitted by atomichydrogen in interstellar space). (b) 1057 MHz (frequency of radiation arisingfrom two close energy levels in hydrogen;known as Lamb shift.) (c) 2.7 K (temperature associated with theisotropic radiation filling all space-thought to be a relic of the ?big-bang? origin of the universe.) (d) (double lines of sodium) (e) 14.4 keV[energy of a particulartransition in nucleus associated witha famous high resolution spectroscopicmethod (Mossbauer spectroscopy).]  

Answer:

(i) Given wavelength is of the order ofi.e. short radio wave. (b) Frequency is of the order of Hzi.e. short radio wave. (c) or Wavelength is of the order of  i.e., microwave. (d) Given wavelengths are of the order of  i.e., visible radiations (Yellow light) (e) Using  we get i.e., The wavelength is of the order of  corresponding to X-rays or soft rays.