PHYSICS UNIT 1-LIGHT PRACTICE QUESTIONS (15) 1.When two lenses 10D and - 20D are kept in contact find focal length. a)- 9 cm b)- 10 cm c)- 11 cm d)- 12 cm 2.Assertion (A) : Light travels faster in glass than in air. Reason (R) : Glass is denser than air. a) Both A and R true and R is the correct explanation of A. b) Both A and R are true but R is not the correct explanation of A. c)A is true but R is false. d) A is false but R is true. 3.In order to obtain a magnification of ( 3) with a convex lens, object should be placed : a) Between optic centre and focus b) Between focus and 2F c) At 2F d)Beyond 2F 4. The refractive indices of four substances P, Q, R and S are 1.77, 1.50, 2.42 and 1.31 respectively. When light travelling in air is incident on these substances at angles, the angle of refraction will be the maximum in : a)P b)Q c)R c) S 5) In the diagram shown below: a) B is incident ray and C is refracted ray. b) A is incident ray and B is refracted ray.
Formatting page ...