Human Eye and Colourful World

What you'll learn

A concept-first Class 10 guide to the human eye, power of accommodation, vision defects and their lens corrections, plus dispersion and scattering that explain rainbows, blue skies and red sunsets.

This chapter has

Human Eye and Colourful World — solved practice questions

8 Class 10 Science questions with step-by-step solutions. Attempt each, then reveal the answer.

1. Q1easy

   The ability of the eye to adjust its focal length to see objects at different distances is called:

   • Apersistence of vision
   • Bdispersion
   • Caccommodation
   • Drefraction
   Show answer & solution

   Correct answer: (C) accommodation

   Power of accommodation — the ciliary muscles change the curvature of the eye lens to focus on near and far objects.

2. Q2easy

   The defect of vision where a person cannot see distant objects clearly is:

   • Amyopia
   • Bhypermetropia
   • Cpresbyopia
   • Dastigmatism
   Show answer & solution

   Correct answer: (A) myopia

   Myopia (near-sightedness) — the image forms in front of the retina; corrected by a concave lens.

3. Q3easy

   Myopia is corrected by using:

   • Aconvex lens
   • Bconcave lens
   • Ccylindrical lens
   • Dbifocal lens
   Show answer & solution

   Correct answer: (B) concave lens

   A concave (diverging) lens diverges light so it forms the image on the retina.

4. Q4easy

   Hypermetropia (long-sightedness) is corrected by:

   • Aconvex lens
   • Bconcave lens
   • Cplane glass
   • Dmirror
   Show answer & solution

   Correct answer: (A) convex lens

   A convex (converging) lens converges light to form the image on the retina.

5. Q5easy

   Splitting of white light into its component colours is called:

   • Areflection
   • Brefraction
   • Cdispersion
   • Dscattering
   Show answer & solution

   Correct answer: (C) dispersion

   Dispersion — a prism splits white light into the seven VIBGYOR colours.

6. Q6medium

   The colours of the rainbow appear in the order:

   • AVIBGYOR
   • BROYGBIV
   • CVBRGIO Y
   • Drandom
   Show answer & solution

   Correct answer: (A) VIBGYOR

   VIBGYOR — Violet, Indigo, Blue, Green, Yellow, Orange, Red — from inner to outer arc of the rainbow.

7. Q7medium

   Which colour of light is deviated (bent) the most by a prism?

   • Ared
   • Bgreen
   • Cviolet
   • Dyellow
   Show answer & solution

   Correct answer: (C) violet

   Violet light has the smallest wavelength and highest refractive index, so it bends the most.

8. Q8medium

   The sky appears blue because of:

   • Ascattering of blue light
   • Breflection of blue light
   • Crefraction
   • Dabsorption of red light
   Show answer & solution

   Correct answer: (A) scattering of blue light

   Rayleigh scattering — shorter-wavelength blue light scatters more off air molecules than red light.

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