Question

PLEASE ANSWER MY ALL QUESTION WITHOUT WRONG ANSWERS...
1. Draw ray diagrams showing the image formation by a concave lens when an object is placed
(a) at the focus of lens
(b) between focus and twice the focal length of the lens
(c ) beyond the twice focal length of lens
2. Define the power of lens. What is its unit? One student uses a lens of focal length 50 cm and another
of focal length -50 cm. What is the nature of the lens and its power used by each of them?
3.Why does the sun appear reddish early in the morning?
4. Why does the sky appear dark instead of blue to the astronaut?
ANSWERING ALL ANSWER IS A MUST WITHOUT ANY WRONG ANSWER ..OR ELSE IT WILL BE REPORTED ...

Answer 1

Answer:

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1. see answer in above pic ok

2.The power of a lens is defined as the reciprocal of the focal length. ... Converging (convex ) lenses have positive focal lengths, so they also have positive power values. Diverging (concave ) lenses have negative focal lengths, so they also have negative power values.

A unit of measurement is a definite magnitude of a quantity, defined and adopted by convention or by law, that is used as a standard for measurement of the same kind of quantity. Any other quantity of that kind can be expressed as a multiple of the unit of measurement. For example, a length is a physical quantity.

Since focal length is negative; the lens is concave. Concave lenses are used to correct myopia.

Power of lens is defined as the ability of a lens to bend the light rays. It is given by the reciprocal of focal length of the lens in meter. Its unit is Diopter. Focal length of lens used by first student is in positive, hence it is a convex lens.

3.During sunrise, the light rays coming from the Sun have to travel a greater distance in the earth's atmosphere before reaching our eyes. In this journey, the shorter wavelengths of lights are scattered out and only longer wavelengths are able to reach our eyes. ... Therefore, the Sun appears reddish early in the morning.

4.Scattering of light is the phenomenon that causes the sky to appear blue. Fine dust in the earth's atmosphere scatters the sunlight. ... Thus, there is no question of scattering of light. Thus, the sky appears dark instead of blue to an astronaut

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