explain delayed sunset and advanced sunrise.... why does it happen( give proper reason).....
the apperent shift in the directionn of sun from its original direction is 0.5 degree and the time difference b?W actual sunrise and apparent sunrise is 2 minutes. this makes the sun visible 2 mins. before it comes out of the horizon ie. advanced sunrise . the same result is obtained during the sunset. the sun can be seen upto 2 mins. of its actual setting.ie.delayed sunrise.thus the day appears to belonger than 4 mins.
hope u understand from concept
Sun can be seen about two minutes before actual sunrise because of refraction of sunlight through the atmosphere. When the sun is just below the horizon, sunlight enters the earth's atmosphere obliquely and gets refracted through the different layers of the atmosphere. As a result of this, sunlight gets bent and reaches the eyes of an observer. Following the path of the light rays entering the eyes, the observer sees the sun slightly above its actual position. As a result of this, sun can be seen about two minutes before the actual sunrise
The Sun is visible to us about 2 minutes before the actual sunrise, and about 2 minutes after the actual sunset because of atmospheric refraction. By actual sunrise, we mean the actual crossing of the horizon by the Sun. The time difference between actual sunset and the apparent sunset is about 2 minutes. The apparent flattening of the Sun’s disc at sunrise and sunset is also due to the same phenomenon.
This is due to the refraction of light coming from the sun.Because when light comes from the sun it generally travel from rarer medium to denser medium i.e., it travels from space[vaccum] to the earth 's atmosphere[full of air].
Advanced sunrise:- it is due to that when the sun is below the horizon at that time the light from the sun enters to earth 's atmosphere from space at get refracted away from the normal line of sun and it causes advanced sunrise.
Delayed sunset:- it is due to the reason that when the sun goes below the horizon at that time the sun 's light pases from space to earth 's atmosphere and it again get refracted from the normal line of the sun and it causes the delayed sunset.
During sunrise, when the sun is just below the horizon, our atmosphere causes the light rays to bend and we see the sun early. Similarly, at sunset, the apparent position of the sun is visible to us and not the actual position due to the same bending of light rays effect.
To sum up, due to refraction we see the sun rise about two minutes before it’s actually there and during sunset we see it for around two minutes more, even though it has already moved from that position.
Similarly, due to atmospheric refraction, the sun can be seen for about two minutes after it sets below the horizon.