Optical Instruments Quiz - CBSE Class 12 Physics

Free practice quiz: Optical Instruments (CBSE Class 12 Physics). 11 multiple-choice questions with answers and explanations. Play online, no sign-up needed.

This CBSE Class 12 Physics practice quiz has 11 multiple-choice questions on Optical Instruments, and 11 of them come with an explanation. Try the 5 sample questions below (tap an option to check yourself), then play the full quiz online. No sign-up needed.

Sample questions

1. Which of the following optical instruments uses a converging lens to magnify a nearby object?

   1. Telescope
   2. Simple Microscope
   3. Compound Microscope
   4. Spectrometer
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   Answer: B. Simple Microscope

   A simple microscope uses a single converging lens to magnify a nearby object. The object is placed within the focal length of the lens.

2. A telescope is used to view distant objects. What type of lens is typically used as the objective lens in a refracting telescope?

   1. Diverging lens
   2. Converging lens
   3. Plano-concave lens
   4. Plano-convex lens
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   Answer: B. Converging lens

   A refracting telescope uses a converging lens as its objective lens to collect and converge light from distant objects, forming a real image.

3. Explain the difference in the image formation between a simple and a compound microscope.

   1. Both form real images
   2. Both form virtual images
   3. Simple microscope forms a real image, compound forms a virtual
   4. Simple microscope forms a virtual image, compound forms a real image
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   Answer: D. Simple microscope forms a virtual image, compound forms a real image

   A simple microscope forms a virtual, magnified image directly, while a compound microscope forms a real, inverted image with the objective lens, which is further magnified by the eyepiece to form a final virtual image.

4. What is chromatic aberration and how is it minimized in optical instruments?

   1. It is the bending of light, minimized by using a single lens
   2. It is the blurring of the image, minimized by using a single lens
   3. It is the splitting of white light, minimized by using achromatic lenses
   4. It is the distortion of the image, minimized by using larger lenses
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   Answer: C. It is the splitting of white light, minimized by using achromatic lenses

   Chromatic aberration is caused by the different wavelengths of light being refracted differently. Achromatic lenses, which combine lenses of different refractive indices, are used to minimize this effect.

5. A Cassegrain telescope utilizes a combination of mirrors to form the image. Describe the configuration of mirrors and the path of light rays in this type of telescope and compare its advantages and disadvantages over a refracting telescope.

   1. Complex detailed explanation needed, no single short answer
   2. Uses two concave mirrors, light reflects twice, offers advantages in size and resolution but is complex to build
   3. Uses two convex mirrors, light reflects once, is less complex but has low resolution
   4. Uses one concave and one convex mirror, light reflects twice, offers high resolution but is very large
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   Answer: B. Uses two concave mirrors, light reflects twice, offers advantages in size and resolution but is complex to build

   The Cassegrain telescope uses a large concave primary mirror and a smaller convex secondary mirror. Light rays reflect off the primary, then the secondary, before forming an image. This configuration allows for a compact design with a long effective focal length and reduced spherical aberration, but it's more challenging to manufacture compared to a refracting telescope.

More questions in this quiz

Answers and explanations are in the full quiz.

1. What is the main function of the eyepiece in a compound microscope?
2. What is the angular magnification of a simple microscope when the final image is formed at the least distance of distinct vision (D)?
3. How does the resolving power of a telescope change if you increase the diameter of the objective lens?
4. Describe the phenomenon of spherical aberration and discuss methods to reduce it in a lens system.
5. What is the difference between a Galilean telescope and a Keplerian telescope? Explain the advantages and disadvantages of each.
6. In a compound microscope, what is the role of the objective lens and the eyepiece lens?

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