12. An observer A sees a source of light and another observer B to be moving...

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12. An observer A sees a source of light and another observer B to be moving in exactly opposite directions with equal speeds of 0.6 c. Observer A measures the wavelength of light as 4000 Å. Calculate the natural frequency of the source and the wavelength of the source as measured by observer B. (Ans. 1.5 x 1015 Hz.; 8000 Å). 13. A beam of light of wavelength 5400 Å sent from the earth is reflected back by a rocket moving with a uniform velocity directly away from the earth. The reflected light is shifted by 1200 Å. Is this shift an increase or a decrease in wavelength? What is the velocity of the rocket? 1+ B Hint: 6600 (Ans. Increase; 0.1 c) 1-B 5400 14. The wavelength of the alpha line of hydrogen is 6560 Å. What will be the measured wavelength of the Ho line in the absorption spectrum of a receding star moving at 3 x 10° m/s away from the earth? (Ans. 6625.6 Å) 12. An observer A sees a source of light and another observer B to be moving in exactly opposite directions with equal speeds of 0.6 c. Observer A measures the wavelength of light as 4000 Å. Calculate the natural frequency of the source and the wavelength of the source as measured by observer B. (Ans. 1.5 x 1015 Hz.; 8000 Å). 13. A beam of light of wavelength 5400 Å sent from the earth is reflected back by a rocket moving with a uniform velocity directly away from the earth. The reflected light is shifted by 1200 Å. Is this shift an increase or a decrease in wavelength? What is the velocity of the rocket? 1+ B Hint: 6600 (Ans. Increase; 0.1 c) 1-B 5400 14. The wavelength of the alpha line of hydrogen is 6560 Å. What will be the measured wavelength of the Ho line in the absorption spectrum of a receding star moving at 3 x 10° m/s away from the earth? (Ans. 6625.6 Å)

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12 This problem is basically Dopplers effect in light Here observer B is travelling towards the source in the opposite direction So v06c The wavelengt... View the full answer