Question 1

Question 6Which of the following lenses would you prefer to use while reading small letters found in a dictionary?A convex lens of focal length 50 cmA concave lens of focal length 50 cmA convex lens of focal length 5 cmA concave lens of focal length 5 cm

Accepted Answer

A convex lens of focal length 5 cmReason — A convex lens gives a magnified image and shorter the focal length, more is the magnification, hence, a convex lens of focal length 5 cm will be preferred.

Web Content: Light: Reflection and Refraction | Bright Tutorials

BRIGHT TUTORIALS

BRIGHT TUTORIALSCBSE Class X | Academic Year 2026-2027
    
    9403781999Excellence in Education
  
  Science | Chapter 9: Light: Reflection and RefractionWeb Content

Chapter 9: Light: Reflection and Refraction &mdash; Quick Revision Guide

Introduction
      Light behaves predictably when it reflects off mirrors and refracts through lenses. This chapter covers the laws of reflection and refraction, image formation by spherical mirrors and lenses, and numerical problem-solving using mirror and lens formulae.

Key Points at a Glance
      
        Laws of reflection: angle of incidence = angle of reflection; incident ray, reflected ray, normal in same plane
        Concave mirror: converging; image depends on object position (6 cases from &infin; to between P and F)
        Convex mirror: always virtual, erect, diminished image; used as rear-view mirror (wider field of view)
        Mirror formula: 1/v + 1/u = 1/f; magnification m = &minus;v/u = h'/h
        Sign convention: object on left &rarr; u negative; concave f negative; convex f positive
        Refraction: bending of light at interface; Snell's law: sin i / sin r = n21; denser medium bends towards normal
        Convex lens: converging; 6 image positions; concave lens: always virtual, erect, diminished
        Lens formula: 1/v &minus; 1/u = 1/f; m = v/u; Power P = 1/f(m); unit: dioptre (D)
        Convex lens: +f, +P; Concave lens: &minus;f, &minus;P; combination: P = P1 + P2

Real-World Connections
      Concave mirrors in solar cookers and headlights; convex mirrors for vehicle rear-view; magnifying glass is a convex lens; spectacles correct vision defects; cameras and projectors use lenses.

Quick Self-Test (5 Questions)
      
        What is the most important concept you learned from this chapter?
        Can you write three key equations/formulae from this chapter from memory?
        Draw a labelled diagram relevant to this chapter without looking at your notes.
        Explain one real-world application of a concept from this chapter.
        What is one common mistake students make in this chapter, and how can you avoid it?

Further Study
      
        NCERT Textbook Chapter 9
        NCERT Exemplar Problems
        Bright Tutorials Detailed Notes: ch09-light-reflection-refraction.html
        Bright Tutorials Practice Questions: ch09-light-reflection-refraction.html
        Previous Year CBSE Board Papers

Bright Tutorials | Hariom Nagar, Nashik Road | 9403781999 | brighttutorials.in

Question 2

Question 7We wish to obtain an erect image of an object, using a concave mirror of focal length 15 cm. What should be the range of distance of the object from the mirror? What is the nature of the image? Is the image larger or smaller than the object? Draw a ray diagram to show the image formation in this case.

Accepted Answer

Concave mirror gives a virtual and erect image only when the object is placed between its pole and focus.Hence, the range of distance of the object should be less than 15 cm from the mirror.Image is virtual.Image is larger than the object.Ray diagram to obtain an erect image using a concave mirror is shown below: