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NCERT Solution

Question 1: Fill in the blanks:

  1. An image that cannot be obtained on a screen is called ____________.
  2. Image formed by a convex __________ is always virtual and smaller in size.
  3. An image formed by a __________ mirror is always of the same size as that of the object.
  4. An image which can be obtained on a screen is called a _________ image.
  5. An image formed by a concave ___________ cannot be obtained on a screen.

Answer: (a) virtual, (b) mirror, (c) plane, (d) real, (e) lens


Question: 2 -Mark ‘T’ if the statement is true and ‘F’ if it is false:

  1. We can obtain an enlarged and erect image by a convex mirror.
  2. A concave lens always forms a virtual image.
  3. We can obtain a real, enlarged and inverted image by a concave mirror.
  4. A real image cannot be obtained on a screen.
  5. A concave mirror always form a real image.

Answer: (a) F, (b) T, (c) F, (d) F, (e) F


Question 3: Match the items given in Column I with one or more items of Column II.

Column IColumn II
(1) A plane mirror(a) Used as a magnifying glass
(2) A convex mirror(b) Can form image of objects spread over a large area
(3) A convex lens(c) Used by dentists to see enlarged image of teeth
(4) A concave mirror(d) The image is always inverted and magnified
(5) A concave lens(e) The image is erect and of the same size as the object
(f) The image is erect and smaller in size than the object

Answer:

1 → e, 2 → b, 3 → a, 4 → c, 5 → f

Question 4: State the characteristics of the image formed by a plane mirror.

Answer: In case of plane mirror, the image is erect, virtual and of same size as the object.

Question 5: Find out the letters of English alphabet or any other language known to you in which the image formed in a plane mirror appears exactly like the letter itself. Discuss your findings.

Answer: Some examples: A, H, I, M, O, T, U, V, W and X

Question: 6: What is a virtual image? Give one situation where a virtual image is formed.

Answer: The image which cannot be obtained on a screen is called virtual image. For example, virtual image is always formed in case of plane mirror and convex mirror.

Question 7: State two differences between a convex and a concave lens.

Answer: A convex lens can make enlarged image, while a concave lens would always make smaller image. A convex lens usually makes real image, while a concave lens always makes a virtual image.



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