Q1. Fill in the blanks.
i. A person 1 m in front of a plane mirror seems to be __ m from his image.
ii. If you touch your ________ ear with right hand in front of a plane mirror it will be seen in the mirror that your right ear is touched with ____________.
iii. The size of the pupil becomes __________ when you see in dim light.
iv. Night birds have _________cones than rods in their eyes.
v. In the iris, there is a small opening called the _________.
vi. The impression of an image does not vanish immediately from the retina. It persists there for about __________ of a second.
vii. If still images of a moving object are flashed on the eye at a rate faster than 16 per second, then the eye perceives this object as ____________.
Q2. State True (T) or False (F).
i. The moon is not an illuminated object. ___
ii. Interesting feature of a kaleidoscope is that you will never see the same pattern again. ___
iii. Sunlight, called white light, consists of eight colours. ___
iv. Visually challenged persons can read and write using Braille system. ___
v. Two mirrors inclined to each other give multiple images. ___
vi. Light is reflected from all surfaces. ___
Q3. Name a device which works on the reflection of reflected light.
Q4. Name the point inside the human eye where no vision is possible.
Q5. Name an eye disease caused by the deficiency of vitamin A in the diet.
Q6. What type of reflection of light takes place from a plane mirror?
Q7. Which part of the eye converges light rays to form the image?
Q8. Where is the image of an object formed in human eye?
Q9. Which part of the eye carries images to the brain?
Q10. How many mirrors are there in a periscope?
Q11. Name an instrument or toy which works by producing multiple reflections from three plane mirrors to form beautiful patterns.
Q12. Angle of incidence is equal to the angle of reflection
(a) Always (b) Sometimes (c) Under special conditions (d) Never
Q13. How many images of a candle will be seen when two mirrors are set parallel to each other and a candle is placed between them?
Q14. What type of reflection of light takes place from a rough surface?
Q15. What type of reflection of light takes place from a smooth surface?
Q16. Which type of reflection of light leads to the formation of images?
Q17. What is an 'incident ray'?
Q18. What kind of lens (convex or concave) is there in our eyes?
Q19. What are the main parts of the human eye?
Q20. What is angle of incidence?