Question

A device used to observe stars and other heavenly bodies is:
(a) periscope
(b) Microscope
(c) Telescope
(d) Compound microscope

Answer 1

Hint: By using basic concepts of lenses used in these terms we will be able to detect which one is correct. Mostly we see stars or moon by using a telescope and by periscope one can see it through if under a submarine. Microscopes and compound microscopes are used for testing samples in the laboratory.

Complete answer:
We are going to answer the question by first understanding all the terms given in the question.

Periscope: This is mainly an apparatus which includes a tube type structure which is attached to a combination of mirrors type object. With the help of this mirror type object anyone who is looking behind the periscope can see those things which are not possible to look at by free eyes. This is used in submarines so; clearly it is not used to watch anybody in the sky.

Microscope: We have seen many times in our life that the microscope is always used to see such small particles around us which is not visible through our free eyes. But such small objects are visible by a microscope only if that object has been kept under it. Since, a heavenly body cannot be placed under it so, it is also not the right option.

Compound microscope: It has also been used to see tiny particles which we cannot see through our eyes in a free space but there is a difference between a compound and a microscope which is that a compound microscope uses 3 to 5 lenses inside it to see things more clearly. Any light source works as an illuminator in it. Clearly, it is also not used to see heavenly bodies in the sky.

Telescope: It is used to see distinct objects which we cannot see through our free eyes. It helps to see the heavenly bodies in the sky by enlarging it with the help of concave and convex lenses. We can also see the diagram for better understanding.

So, the correct answer is “Option C”.

Note:
As a student of physics one should be familiar with the terms involved in the options. With some basic definitions of these terms one can easily answer the question by either discarding wrong options or by directly selecting the right option. Lenses are used in many objects most importantly to be able to see those objects which cannot be seen from bare eyes. As very tiny objects as well as the heavenly bodies in the sky both are not in the visible range of our eyes. So, the lenses are adjusted in technologies so that one can see these by making its image more enlarged and magnified by using either a concave lens or a convex lens.