Optics Question 243
Question: A star emits light of $ 5500{AA} $ wavelength. Its appears blue to an observer on the earth, it means
[DPMT 2002]
Options:
A) Star is going away from the earth
B) Star is stationary
C) Star is coming towards earth
D) None of the above
Show Answer
Answer:
Correct Answer: C
Solution:
Blue radiations have the wavelength around 4600 $ \overset{o}{\mathop{A}} $ . It shows that apparent wavelength is smaller than the real wavelength. It means that the star is proceeding towards earth.
