Question

A) Read the passage given below and answer the questions that follow. 5

Mirrors have been used since ages. It is said Archimedes used huge mirrors to focus the heat of the sun’s

rays on enemy ships to burn them. The same principle is used in solar cooker, where mirrors are used to

reflect and focus the sun’s rays on to cooking containers. Astronomers use huge concave mirrors to

focus starlight. The mirrors used in telescope are polished by giving a thin coat of silver or aluminum to

the glass. With the telescope astronomers can see the heavenly bodies, but even without the telescopes

one can see the moon. A full moon shining overhead is a beautiful sight. But it is also a puzzle, because if

the sun and the moon both give the same light, then why is the moonlight more pleasant? The reason is

that the moon reflects very little sunlight, in fact, only seven percent of the light it receives. The earth

reflects about half of the radiation that it receives from the sun. Imagine how bright the earth must be

looking from the moon! The bright crescent is illuminated by the sun. The rest of the moon is

illuminated by earthlight. In other words, the light reflected by the earth is falling on the moon. This is

being reflected back to us and is strong enough to show the moon faintly. As the crescent increases in

size, this effect disappears.

Fresh snow is the best reflector of sunlight in nature. As a highly reflective substance, snow dramatically

increases UV-B exposure near the Earth’s surface, as it reflects most of the radiation back into the

atmosphere, where it is hen scattered back towards the surface by aerosols and molecules. Fresh snowcan reflect as much as 94 percent of the incoming UV radiation. The bright light reflected by it can dazzle

and harm your eyes. Mountaineers, therefore, use dark glasses.

Answer the following questions:

1) Mirrors used in telescope are polished by which coating?

2) With the astronomers can see the heavenly bodies.

a) telegraph b) telephone c) telescope d) television.

3)The principle of focusing the sun rays is used in_ .

a) Inverter b) Pressure Cooker c) Solar Cooker d) None of the above

4) Mountaineers wear _ while climbing mountains.

5) How did Archimedes use mirrors to focus the heat of the sun rays?​

Answer 1

Answer:

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Explanation:

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