Question

Atmospheric refraction is the phenomenon of bending of light on passing through earth's atmosphere. As we move above the surface of earth, density of air goes on decreasing. Local conditions like temperature etc. also affect the optical density of earth's atmosphere. On account of atmospheric refraction, stars seen appear higher than they actual are; advanced sunrise; delayed sunset, oval appearance of the sun

at sunrise and sunset; stars twinkle, planets do not.

1) Due to atmospheric refraction, apparent length of the day.

a) increases

b) decreases

c) remains the same

d) any one of the above

2) Apparent position of the star appears raised dur to

a) atmospheric refraction

b) total internal reflection of light

c) scattering of light

d) None of the above

3) The sun spears oval shaped or flattened dur to atmospheric refraction only

a) true always

b) false always

c) true sometimes

d) cannot say​

Answer 1

1)

Correct option:

a) increases

( Due to atmospheric refraction, the sun remains visible even after it sets and is visible even before it rises. Thus, the refraction increases the length of the day.)

2)

Correct option:

a) atmospheric refraction

(A star appears slightly higher than its actual position in the sky because of the atmospheric refraction, the star seems to be higher in the sky than the actual position.)

3)

Correct option:

c) true sometimes

(The rays of light from the upper part and lower part of the periphery of the sun bend unequally on traveling through earth's atmosphere. That is why the sun appears oval or flattened at the time of sunrise and sunset.)