Light Worksheet-3

Light Worksheet-3

1. When a parallel beam of light on striking some rough surface bounces off in different directions, the phenomenon is called :

(a) rough reflection                      (b) normal reflection

(c) regular reflection                   (d) irregular reflection

2. Which will not cause irregular reflection?

(a) Tissue paper                            (b) Rough piece of wood

(c) Still water                                (d) An old newspaper

3. Rectilinear propagation of light means that light travels in

(a) rectangles                                (b) straight lines

(c) curved path                             (d) None of these

4. A shadow is formed only if :

(a) there is a source of light

(b) there is a source of light and an opaque body to obstruct light

(c) there is a source of light, an opaque body to obstruct light and a screen

(d) Any of these

5. The old unit of intensity of light is :

(a) inch candle                              (b) yard candle

(c) foot candle                               (d) None of these

6. The modern unit of intensity of light is :

(a) watt                                           (b) foot candle

(c) lux                                              (d) None of these

7. From the diagram below, given that PQ is a plane mirror, which is the normal ray?

(a) AX                 (b) BX                (c) XC                 (d) AC

8. Rainbow is produced when sunlight falls on drops of rain. Which of the physical phenomena are responsible for this?

(a) Diffusion

(b) Refraction and internal reflection

(c) Only refraction

(d) Diffusion, refraction and total internal reflection

9. An object is placed at centre of curvature C of a concave mirror, the image will be formed

(a) at Focus                                    (b) at Infinity

(c) Between C and F                    (d) at C

10. From the diagram below, what is the angle of incidence?

(a) 25º                (b) 50º               (c) 65º                (d) 90º

Answer Key:

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