explain how does the refraction of light affect the length of the day class 12
How does the refraction of light affect the length of the day? (Class 12)
Answer:
The refraction of light plays an important role in determining the length of the day. Refraction is the bending of light as it passes through different mediums, such as air, water, or glass. This bending of light can have an impact on the phenomenon of sunrise and sunset, thus affecting the length of the day.
When sunlight passes through the Earth’s atmosphere, it undergoes refraction due to the variation in air density at different altitudes. This refraction causes the path of light to bend slightly, which results in the apparent position of the Sun being slightly higher than its actual position. As a result, we observe the Sun to rise earlier and set later than its true position.
This apparent shift in the position of the Sun affects the duration of daylight hours. Due to the refraction of light, the Sun appears to be slightly above the horizon even before it actually rises and after it sets. This extended presence of sunlight contributes to longer daylight hours.
In the morning, the Sun rises earlier than it would without refraction, and in the evening, it sets later. This phenomenon is more noticeable at higher latitudes closer to the poles, where the Sun’s path is at a shallower angle with the horizon.
It is important to note that the amount of refraction depends on several factors, including the angle at which the Sun’s rays enter the Earth’s atmosphere, the atmospheric conditions, and the wavelength of light. Hence, the extent to which refraction affects the length of the day may vary on different days and at different locations.
In summary, the refraction of light in the Earth’s atmosphere causes the apparent position of the Sun to be slightly higher than its true position. This results in the Sun rising earlier and setting later than it would without refraction, contributing to longer daylight hours.