Question

Is the position of a star as seen by us its true position? Explain your answer. A. A. Yes, due to refraction
B. No, due to transmission
C. No, due to refraction
D. Yes, due to transmission

Answer 1

Hint: Try to understand the concept of refraction. Due to refraction light changes its original path. Refractive index of the inner layers in the earth’s atmosphere and the refractive index of the outer atmosphere are different from each other. Apparent position of the star is not its original position.

Complete answer:
When the light of a star enters the atmosphere of the earth from the outer atmosphere then it undergoes refraction because the refractive index of earth’s atmosphere is different from the outer atmosphere. The change in refractive index between the mediums becomes the main reason for refraction of light. There are many layers in the earth’s atmosphere, so the light undergoes refraction many times and its refractive index continuously changes. That’s why we see the different apparent position of the star instead of its actual position.

So, the correct answer is “Option C”.

Additional Information:
Light of the star moves towards the normal after entering into the earth’s atmosphere because the refractive index of the outer atmosphere is greater than the earth’s atmosphere. Therefore, the position of the star appears slightly different from the actual position of the star. Also, the star appears higher than its actual position.

Note:
In this question you are asked to find, is the position of a star as seen by us is true or not? Here, our main focus on how the position of the star appears different from its actual position. The change of refractive index in different mediums of layers in the atmosphere becomes the main reason for a star’s appearance instead of its original position.