Applications of Mirrors and Lenses MCQs Quiz | Class 10

This quiz covers Class X Science (Code 086), Unit III: Natural Phenomena, focusing on the Topic: Applications of Mirrors and Lenses. It specifically includes use-cases in daily life. Test your knowledge and download a detailed answer PDF for revision.

Educational Content: Applications of Mirrors and Lenses

Overview

Mirrors and lenses are fundamental optical components that play crucial roles in our daily lives, from simple reflections to complex optical instruments. Understanding their properties and applications is key to comprehending how light behaves and how we manipulate it for various purposes.

Key Concepts

  • Reflection: The bouncing back of light when it strikes a surface. Governed by laws of reflection, critical for mirrors.
  • Refraction: The bending of light as it passes from one medium to another. Governed by laws of refraction (Snell’s Law), critical for lenses.
  • Image Formation: How optical devices create images (real/virtual, erect/inverted, magnified/diminished).

Applications of Mirrors

1. Plane Mirrors

These mirrors produce virtual, erect, and same-sized images. They are commonly used in:

  • Dressing tables: For viewing oneself.
  • Periscopes: To see objects over obstacles.
  • Kaleidoscopes: To create multiple reflections and patterns.

2. Concave Mirrors (Converging Mirrors)

Concave mirrors converge parallel rays of light to a single focal point. Their image formation properties vary with object distance, allowing them to form both real and virtual images. Uses include:

  • Shaving mirrors and dental mirrors: To get a magnified image of the face or teeth.
  • Solar furnaces/cookers: To concentrate sunlight at a focal point to generate heat.
  • Headlights of cars and searchlights: To produce a powerful, parallel beam of light (when the light source is placed at the focus).

3. Convex Mirrors (Diverging Mirrors)

Convex mirrors diverge parallel rays of light and always form virtual, erect, and diminished images. They offer a wider field of view.

  • Rear-view mirrors in vehicles: To provide the driver with a wider view of traffic behind.
  • Security mirrors in shops: To monitor a large area of the store.
  • Street light reflectors: To spread light over a large area.

4. Parabolic Mirrors

These are a special type of concave mirror that completely eliminates spherical aberration, ensuring all parallel rays converge perfectly at the focus. Applications include:

  • Reflecting telescopes: For astronomical observations.
  • Satellite dishes: To collect weak radio signals and focus them onto a receiver.
  • High-end car headlights: To produce a very sharp and parallel beam.

Applications of Lenses

1. Convex Lenses (Converging Lenses)

Convex lenses converge parallel rays of light to a single focal point. They are used in various optical instruments and for vision correction.

  • Magnifying glasses: To produce magnified virtual images of small objects.
  • Cameras, microscopes, telescopes, and projectors: As primary components to form images.
  • Spectacles for hypermetropia (long-sightedness): To correct vision by converging light onto the retina.

2. Concave Lenses (Diverging Lenses)

Concave lenses diverge parallel rays of light and always form virtual, erect, and diminished images.

  • Spectacles for myopia (short-sightedness): To correct vision by diverging light before it reaches the retina.
  • Peepholes in doors: To provide a wider, diminished view of the outside.
  • Galileo’s telescope: Used as the eyepiece.

Summary Table of Key Applications

Optical Component Type Primary Use Cases Common Image Characteristics
Plane Mirror Reflector Dressing mirror, periscope Virtual, erect, same size
Concave Mirror Reflector Shaving mirror, dental mirror, solar furnace, headlights Variable (magnified/real/inverted)
Convex Mirror Reflector Rear-view mirror, security mirror, street lights Virtual, erect, diminished
Convex Lens Refractor Magnifying glass, camera, microscope, hypermetropia correction Variable (magnified/real/inverted)
Concave Lens Refractor Myopia correction, peephole Virtual, erect, diminished

Quick Revision Points

  • Mirrors reflect light; lenses refract light.
  • Concave mirrors and convex lenses are converging (focus light).
  • Convex mirrors and concave lenses are diverging (spread light).
  • Real images can be projected onto a screen; virtual images cannot.
  • Myopia (short-sightedness) is corrected with a concave lens.
  • Hypermetropia (long-sightedness) is corrected with a convex lens.

Extra Practice Questions

  1. Why do dentists use concave mirrors?

    • a) To see a wide view of the mouth.
    • b) To get a diminished image of the teeth.
    • c) To get a magnified image of the teeth.
    • d) To reflect light brightly onto the teeth.

    Answer: c) To get a magnified image of the teeth.

  2. A person suffering from long-sightedness (hypermetropia) would typically use spectacles with:

    • a) Concave lenses
    • b) Convex lenses
    • c) Bifocal lenses
    • d) Cylindrical lenses

    Answer: b) Convex lenses

  3. Which application demonstrates the concentrating property of a concave mirror?

    • a) Rear-view mirror
    • b) Security mirror
    • c) Solar cooker
    • d) Dressing table mirror

    Answer: c) Solar cooker

  4. The field of view of a convex mirror is:

    • a) Narrower than a plane mirror
    • b) Wider than a plane mirror
    • c) Same as a plane mirror
    • d) Depends on the object distance

    Answer: b) Wider than a plane mirror

  5. Which optical instrument uses a combination of convex lenses to produce a highly magnified image of tiny objects?

    • a) Telescope
    • b) Periscope
    • c) Microscope
    • d) Camera

    Answer: c) Microscope