Optics Question 15
Question: Assertion : The polar caps of earth are cold in comparison to equatorial plane. Reason : The radiation absorbed by polar caps is less than the radiation absorbed by equatorial plane.
Options:
A) If both assertion and reason are true and the reason is the correct explanation of the assertion.
B) If both assertion and reason are true but reason is not the correct explanation of the assertion.
C) If assertion is true but reason is false.
D) If the assertion and reason both are false.
E) If assertion is false but reason is true.
Show Answer
Answer:
Correct Answer: C
Solution:
Polar caps receives almost the same amount of radiation as the equatorial plane.
For the polar caps angle between sun rays and normal (to polar caps) tends to 90°.
As per Lambert’s cosine law, $ E\propto \cos \theta , $ therefore E is zero. For the equatorial plane, q = 0°, therefore E is maximum.
Hence polar caps of earth are so cold. (where E is radiation received).
