CBSE Class 10 Science: Light — Reflection and Refraction — Important Questions with Answers 2026

Short Answer Questions (2-3 Marks)

• Q: State the laws of reflection. Define angle of incidence and angle of reflection.
  Ans: Laws of reflection: (1) The angle of incidence equals the angle of reflection (∠i = ∠r). (2) The incident ray, reflected ray, and normal at the point of incidence all lie in the same plane. Angle of incidence: angle between incident ray and normal to the surface at the point of incidence. Angle of reflection: angle between reflected ray and normal.
• Q: Write the mirror formula and magnification formula for spherical mirrors.
  Ans: Mirror formula: 1/v + 1/u = 1/f, where v = image distance, u = object distance, f = focal length. Magnification: m = -v/u = h'/h (h' = image height, h = object height). Sign convention: distances measured from pole; in front of mirror = negative. For concave mirror: f is negative. For convex mirror: f is positive.
• Q: An object is placed 20 cm from a concave mirror of focal length 15 cm. Find the image position, nature, and magnification.
  Ans: Given: u = -20 cm, f = -15 cm. Using 1/v + 1/u = 1/f: 1/v + 1/(-20) = 1/(-15). 1/v = -1/15 + 1/20 = (-4+3)/60 = -1/60. v = -60 cm. Image is real (v is negative), inverted, on the same side as object. Magnification m = -v/u = -(-60)/(-20) = -3 (inverted, magnified 3 times).

Long Answer / Application Questions (4-6 Marks)

• Q: Distinguish between concave mirror and convex mirror. State one use of each.
  Ans: Concave mirror: Converging mirror, reflecting surface is inner curved surface. Forms real/virtual images depending on object position. Uses: shaving mirror, dentist's mirror, headlights, solar concentrators. Convex mirror: Diverging mirror, reflecting surface is outer curved surface. Always forms virtual, erect, diminished image. Uses: rear-view mirror in vehicles (wide field of view), security mirrors in shops.

Exam Tips for This Chapter

• Revise all definitions and laws from Light — Reflection and Refraction — they are commonly asked as 1-2 mark questions
• Practice diagrams related to Light — Reflection and Refraction — neat labelled diagrams carry 2-3 marks
• For numericals, always show formula → substitution → answer with correct units
• Previous year analysis shows Light — Reflection and Refraction carries 8-12 marks in the board exam