Question 10: Rays from Sun converge at a point 15 cm in front of a concave mirror. Where should an object be placed so that size of its image is equal to the size of the object?
Answer: (b) 30 cm in front of the mirror
Question 11: A full length image of a distant tall building can definitely be seen by using
Answer: (b) a convex mirror
Question 12: In torches, search lights and headlights of vehicles the bulb is placed
Answer: (b) very near to the focus of the reflector
Question 13: The laws of reflection hold good for
Answer: (d) all mirrors irrespective of their shape
Question 14: The path of a ray of light coming from air passing through a rectangular glass slab traced by four students are shown as A, B, C and D in following figure. Which one of them is correct?
Answer: (b) B
Question 15: You are given water, mustard oil, glycerine and kerosene. In which of these media a ray of light incident obliquely at same angle would bend the most?
Answer: (d) Glycerine
Explanation: Ray of light bends at maximum angle in liquid having highest refractive index.
Refractive index of liquids given in the option:
Mustard oil: 1.464M
Since, the refractive index of glycerine is maximum, thus light bends at maximum angle in glycerine.
Question 16: Which of the following ray diagrams is correct for the ray of light incident on a concave mirror as shown in following figure?
Answer: (d) Fig. D
Question 17: Which of the following ray diagrams is correct for the ray of light incident on a lens shown in following figure?
Answer: (a) Fig. A.
Question 18: A child is standing in front of a magic mirror. She finds the image of her head bigger, the middle portion of her body of the same size and that of the legs smaller. The following is the order of combinations for the magic mirror from the top.
Answer: (c) Concave, plane, and convex
Question 19: In which of the following, the image of an object placed at infinity will be highly diminished and point sized?
Answer: (d) Concave mirror, convex mirror, concave lens and convex lens
Note: All figures on this page are taken from NCERT Exemplar Problems Class 10 Science Book
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