Optical instruments–9th Standard Science Question Bank

Optical instruments

Choose the correct alternatives given for each .

1.The optical instrument used to view cricket match is ---------

a) Simple microscope b) Compound microscope

c) astronomical telescope d) binocular

2. Telescopes makes the far objects appear -----

a) farther b) nearer c) highly magnified d) diappear

3. The type of lens used as a simple microscope ----------

a) binocular lens b) plano concave lens c) concave convex lens d) convex lens

4. The final image in a compound microscope is --------

a) real & inverted b) virtual & inverted c) real & erect d) virtual & erect

Fill in the blanks

1. Name an optical instrument which is used to see erect image of a distance object is -------- ( telescope )

2. The type of lens used to make objective of an astronomical telescope is ----------- ( Biconvex lens )

3. The lens placed towards the object in an optical instrument is called ------ ( objective )

4. The first telescope was designed by ---------- ( John Lippershy )

Match the followings .

1.Simple microscope - virtual & magnified image

2. compound microscope -  real & highly magnified image

3. Astronomical telescope - virtual & diminished image

4. Binocular  - erect & magnified image

Answer the followings

1. What are optical instruments ?

The instruments like Simple microscope, compound microscope, Astronomical telescope, Binocular are called optical instruments.

2. What is a microscope ?

The optical instrument used to see micro objects clearly is called a microscope.

3. Name types of microscopes .

Simple microscope & compound microscope

4. With the help of a ray diagram show the formation of an image in simple microscope.

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5. List the uses of simple microscope.

a) Used by watch repairers & jewellers.

b) used to read small letters.

c) used by palmists to read lines in a palm.

d) used to observe parts of flower.

6. With the help of a ray diagram show the formation of an image in compound microscope.

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7. List the uses of compound microscope.

a) used to see tiny objects.

b) used to see germs, plant cells, blood corpuscles etc.

8. Write the differences between simple microscope & compound microscope.

a) In simple microscope it has only one lens but compound microscope has two lenses.

b) Magnifying power of simple microscope is less compared to Magnifying power of compound microscope (20 times to 500 times )

9. What is a telescope ?

The optical instrument used to see farther celestrial objects like stars, plantes, satellites clearly is called a telescope.

10. Name types of telescopes.

Astronomical telescope. terrestrial telescope & binocular.

11. With the help of a ray diagram show  the formation of an image in astronomical telescope.

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12. With the help of a ray diagram show the formation of an image in terrestrial telescope.

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13. What is a Photographic Camera ?

The optical instrument used to obtain permanent image of an object or a scene is called a Photographic Camera.

14. Write the differences between astronomical telescope & terrestrial telescope.

a) In astronomical telescope inverted image is obtained but in terrestrial telescope erected image is obtained

b) terrestrial telescope is used to see objects on earth but astronomical telescope is used to see terrestrial objects.

15. Mention any uses of a binocular.

a) binocular used in field work like military operations.

b) binocular used to see distant animals in wild life safari.

c) binocular used in playground to watch matches.

16. Write the differences between binocular & terrestrial telescope.

a) in binocular prisms are used but in terrestrial telescopes lenses are used.

b) power of binocular is less but power of terrestrial telescope is more.