MCQ on Atmospheric refraction and twinkling of stars

MCQ on Atmospheric refraction and twinkling of stars

MCQ on Atmospheric refraction and twinkling of stars. Practice Atmospheric refraction and twinkling of stars Multiple Choice Questions and Explanation.

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Atmospheric refraction and twinkling of stars

MCQs

Students in this part we are going to learn the interesting phenomena takes place around us in the form of multiple choice questions. So think on each option and find the most appropriate answer for following questions.

Q.1) Which among the following acts as rarer medium?

a) hot air b) cool air           c) hot water           d) cold water

Ans: a)

Explanation: a) refractive index of hot water decreases hence it become rarer medium

Q.2) When temperature of the material medium through which light is travels, refractive index of the medium is

a) remains same b) increases           c) decreases           d) cannot predicted

Ans: c)

Explanation: c) rise in temperature reduces the refractive index of material medium.

Q.3) When a ray of light travels from optically rarer medium to optically denser medium, the refracted ray……

a) bends away from normal b) bends towards normal c) traces the same path

d) all of these

Ans: b)

Explanation: b) rays of light bends towards normal if it travels from optically rarer to denser medium.

Q.4) If rays of light strikes perpendicular to surface, then refracted ray……

a) bends away from normal b) bends towards normal c) traces the same path

d) all of these

Ans: c)

Explanation: c) as ray of light is along the normal, angle of incidence is 00, hence the angle of refraction also 00 and rays travels the same path.

Q.5) When rays of light passing from denser to rarer medium, its path is…….

a) inclined away from normal b) inclined towards normal c)travels parallel to normal

d) none of these

Ans: a)

Explanation: a) when a ray of light travels from denser to rarer medium, refracted ray bends away from normal.

Q.6) Refractive index of all the different layers of atmosphere is different due to change in….

a) temperature b) different gases c) different densities of gases    d) all of these

Ans: d)

Explanation: d) factors like temperature, material and its density affects the refractive index.

Q.7) An electricity pole observed through flame of ‘Holi fire’ appears to be fluctuating is because of………..

a) Continuous change in direction of light from hot air to cold air and vice versa

b) electricity pole bends due to temperature

c) it is due to the illusion created by flame d) this is not relevant with refraction

Ans: a)

Explanation: d) rays of light sometimes travels from hot (rarer medium) air to cold (denser medium) or vice versa so the path of refracted ray appears to change continuously.

Q.8) Harshit is trying to observe the star in sky, but he finds that position of star is changes continuously, it happens due to…..

a) reflection of light from star b) atmospheric refraction c) scattering of light

d) dispersion of light

Ans: b)

Explanation: b) due to changes in refractive indices of atmospheric layers, the position of star appears different than its actual position.

Q.9) Colder layers of air present in atmosphere are considered as………………..medium.

a) Optically denser b) optically rarer c) optically opaque         d) crystalline

Ans: a)

Explanation: a) cold air has more refractive index hence acts as optically denser medium

Q.10) Stars appears to be twinkle at night is because of…….

a) reflection of light from star b) atmospheric refraction c) scattering of light

d) dispersion of light

Ans: b)

Explanation: b) due to changes in refractive indices of atmospheric layer, light emitted by stars sometimes bends towards normal or sometimes bends away from normal, which changes position of star, and appears to be twinkle.

Q.11) Continuous deviation of light through different densities of layers of atmosphere is due to….

a) refraction of light b) reflection of light c) scattering of light        d) atmospheric refraction.

Ans: d)

Explanation: c) due to change in refractive indices of air, path of light gets deviated continuously.

Q.12) Light emitted from star travels from…………. medium.

a) vacuum to denser b) vacuum to rarer c) rarer to denser   d) denser to rarer

Ans: b)

Explanation: b) outer layers of atmosphere acts as rarer medium as they receive more heat from sun.

Q.13) Planets do not twinkle because of…

a) planets are closer to earth than stars b) planets are bigger in size c) they reflects the light coming from d) all of these

Ans: d)

Explanation: d) planets are considered as collection of large number of stars, so they emit steady intensity of light.

Q.14) At the time of sunrise and sunset, the rays are appears to travel……..path due to refraction from atmosphere

a) random b) straight line c) curve                 d) zigzag

Ans: c)

Explanation: c) due to continuous refraction from atmosphere the path of ray appears like curve to reach the observer.

Q.15) Sun can be visible almost 2 minute before actual time of sunrise due to refraction of sunrays from atmosphere changes the position is known as….

a) early sunrise b) sun shift c) refraction of sunrays    d) advanced sunrise

Ans: d)

Explanation: d) appearance of sun 2 minutes before its actual time of sunrise is called as advanced sunrise.

Q.16) Total duration of day increases by ……. minutes due to advanced sunrise and delayed sunset.

a) 2 b) 4 c) 5             d) 8

Ans: b)

Explanation: b) 2 minute during sunrise and 2 minutes during sunset increase total duration of day by 4 minutes.

Q.17) The flattening of the Sun’s disc at sunrise and sunset is due to…..

a) advanced sunrise b) delayed sunset 3) atmospheric refraction d) all of these

Ans: d)

Explanation: b) appearance of flattening of Sun’s disc is due to atmospheric refraction, which also causes the advance sunrise and delayed sunset.

Updated: May 3, 2021 — 11:03 pm