Question 1: Which of the following can make a parallel beam of light when light from a point source is incident on it?
Answer: (a) Concave mirror as well as convex lens
Question 2: A 10 mm long awl pin is placed vertically in front of a concave mirror. A 5 mm long image of the awl pin is formed at 30 cm in front of the mirror. The focal length of this mirror is
Answer: (b) – 20 cm
Explanation: Given, height of object = 10 mm, height of image = 5 mm, image distance = -30 cm,
Or, `u=-(30)/(0.5)=-60` cm
Mirror formula `1/v+1/u=1/f`
Or, `f=-20` cm
Question 3: Under which of the following conditions a concave mirror can form an image larger than the actual object?
Answer: (c) & (b)
Explanation: In both the cases image formed is larger than object.
Question 4: Following figure shows a ray of light as it travels from medium A to medium B. Refractive index of the medium B relative to medium A is
Answer: (a) `(sqrt3)/(sqrt2)`
Explanation: As per Snell’s Law,
Question 5: A light ray enters from medium A to medium B as shown in following figure. The refractive index of medium B relative to A will be
Answer: (a) Greater than unity
Question 6: Beams of light are incident through the holes A and B and emerge out of box through the holes C and D respectively as shown in following figure. Which of the following could be inside the box?
Answer: (a) A rectangular glass slab
Question 7: A beam of light is incident through the holes on side A and emerges out of the holes on the other face of the box as shown in following figure. Which of the following could be inside the box?
Answer: (d) Convex lens
Question 8: Which of the following statements is true?
Answer: (a) A convex lens has 4 dioptre power having a focal length 0.25 m
Question 9: Magnification produced by a rear view mirror fitted in vehicles
Answer: (a) is less than one
Note: All figures on this page are taken from NCERT Exemplar Problems Class 10 Science Book
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