Class 10 Light: Refraction, Lenses and Refractive Index

0 of 12 answered0 correct
  1. 1
    Question 1

    A pencil standing in a glass of water looks bent at the water surface. What causes this?

  2. 2
    Question 2

    A ray of light passes obliquely from air into glass. Which way does it bend?

  3. 3
    Question 3

    The refractive index of glass is 1.5 and the speed of light in air is 3 × 10⁸ m/s. What is the speed of light in the glass?

  4. 4
    Question 4

    Which statement is Snell's law of refraction?

  5. 5
    Question 5

    The table gives the refractive index of four media. About how many times faster does light travel in water than in diamond?

    A table of four media and their refractive indices: water 1.33, kerosene 1.44, crown glass 1.52 and diamond 2.42.
  6. 6
    Question 6

    The diagram shows an object placed beyond 2F in front of a convex lens. Where is the image formed, and what is it like?

    A convex lens on a principal axis with F and 2F marked on both sides. An upright arrow object stands beyond 2F on the left, with two principal rays drawn from its tip through the lens. No image is drawn.
  7. 7
    Question 7

    The diagram shows an object placed between the optical centre and F of a convex lens. Where is the image formed, and what is it like?

    A convex lens on a principal axis with F and 2F marked on both sides. An upright arrow object stands between the lens and F on the left, with two principal rays drawn from its tip. No image is drawn.
  8. 8
    Question 8

    The diagram shows an object in front of a concave lens. Where is the image formed, and what is it like?

    A concave lens on a principal axis with F and 2F marked on both sides. An upright arrow object stands on the left, with two principal rays drawn from its tip through the lens. No image is drawn.
  9. 9
    Question 9

    The diagram shows an object placed exactly at 2F in front of a convex lens. Where is the image formed, and what is it like?

    A convex lens on a principal axis with F and 2F marked on both sides. An upright arrow object stands exactly on the 2F mark on the left, with two principal rays drawn from its tip. No image is drawn.
  10. 10
    Question 10

    A ray of light passes through a rectangular glass slab. How does the emergent ray compare with the incident ray?

  11. 11
    Question 11

    To use a convex lens as a magnifying glass, where must the object be placed?

  12. 12
    Question 12

    A lens is thicker at the edges than in the middle. What kind of lens is it, and what does it do to parallel rays?