Light Worksheet-5

Light Worksheet-5

1. Which of the following states the second law of reflection correctly?

(a) Incident ray, reflected ray and the normal drawn at the point of incidence to the reflecting surface, lie in the same plane

(b) Incident ray, reflected ray and the normal are always perpendicular to each other

(c) Incident ray and reflected ray lie in same plane which are perpendicular to the normal drawn at the point of incidence

(d) None of these

2. The experiment in the diagram shows that

(a) Light rays are very thin

(b) A beam of light is made up of lots of light rays

(c) Light rays travel in straight lines

(d) The eye can see through the cardboards.

3. The image in a plane mirror is

(I)     Upright

(II)   Real

(III)  The same size as the object

(IV)  As far behind the mirror as the object is in front of it

(a) (I) only                                      (b) (I), (II) and (III)

(c) (I), (III) and (IV)                    (d) All of these

4. The diagram shows a ray of light reflected at a plane mirror. Which pair of the angles of incidence and angles of reflection is correct?

(a) Angle of incidence = 30° and Angle of reflection = 30°

(b) Angle of incidence = 30° and Angle of reflection = 60°

(c) Angle of incidence = 60° and Angle of reflection = 30°

(d) Angle of incidence = 60° and Angle of reflection = 45°

5. An optician holds a test card 50 cm behind a patient. The patient then looks in the plane mirror which is 100 cm away. How far away from the patient's eyes is the image of the test card?

(a) 100 cm         (b) 150 cm         (c) 200 cm        (d) 250 cm

6. Two plane mirrors AB and CD are placed at right angles to one another. A ray of light PQ hits AB at Q making an angle of 45° as shown in the diagram. This ray will be reflected from mirror BD at an angle

(a) 20°                (b) 35°                (c) 45°                (d) 60°

7. For the myopic eye, the defect is cured by

(a) Convex lens                             (b) Concave lens

(c) Cylindrical lens                       (d) None of these

8. The diagram shows a ray PQR travelling through a glass block. Which option in the table gives the correct name for all three rays?

(a) P-Incident ray, Q-Emergent ray, R-Refracted ray

(b) P-Incident ray, Q-Refracted ray, R-Emergent ray

(c) P-Emergent ray, Q-Incident ray, R-Refracted ray

(d) P-Emergent ray, Q-Refracted ray, R-Incident ray

9. Light travel at different speeds in different materials (mediums). Which is the correct order of increasing speed of light in the following materials?

(a) Air, water, glass                     (b) Water, air, glass

(c) Water, glass, air                     (d) Glass, water, air

10. The hole in the eye that controls the amount of light that enters is

(a) Iris                (b) Pupil            (c) Cornea         (d) Retina

Answer Key:

(1)-(a); (2)-(c); (3)-(c); (4)-(a); (5)-(d); (6)-(c); (7)-(b); (8)-(b); (9)-(d); (10)-(a)