Lakhmir Singh and Manjit Kaur Science solution: Light Chapter 16. Here you get easy solutions of Lakhmir Singh and Manjit Kaur Science solution Chapter 16 . Here we give Chapter 16 all solution of Class 8. Its help you to complete your homework.
Board – CBSE
Text Book – SCIENCE
Class – 8
Chapter – 16
VERY SHORT ANSWER TYPE QUESTIONS answer
1) The ray of light which falls on the mirror surface is called incident ray.
2) The ray of light which is sent back by the mirror is called reflected ray.
4) The point at which the Incident ray strikes the mirror is called the point of incidence.
5) Imaginary line.
6) The angle between incident ray and normal is called the angle of incident.
7) The angle between reflected ray and normal is called the angle of reflection.
10) The light will go straight.
15) (a) irregular surface.
(b) regular surface.
16) Regular reflection.
17) a> Diffuse reflection. b> Regular reflection.
20) Lateral inversion.
22) a> parallal. b> 45
25) Kaleidoscope are used by designers of wall papers and fabrics.
26) Glass prism.
27) Seven color is formed.
29) 25 cm
30) Blind spot.
32) night blindness.
36) Cornia, Iris, Eye lense.
39) a> True, b> False, c>True.
40) a> incidence, b> 2, c> Left; Left hand, d> Large. e>fewer, f> 1∕16, g>16, h> 24
SHORT ANSWER TYPE QUESTIONS Answer
41) No, we cannot see the objects in a dark room.
If there is a light outside the room, then we can watch the objects outside the room.
When light reflects from a object in our eyes then we can see the objects. If there is no reflects of light from any objects then we cannot see any kind of objects.
42) When light reflects from a object in our eyes then we can see the objects. If there is no reflects of light from any objects then we cannot see any kind of objects. This thing makes visible to us.
43) We are able to see the moon because of the light that it receives from the sun when it revolves around our planet and without the presence of the light of the sun then we cannot see the moon.
44) regular reflection and diffuse reflection.
Regular reflection makes us to see an object from all direction.
45) The wall have diffuse reflection and the mirror have regular reflection.
46) It is because the light in this room is reflects all the side from the book. That’s why a book lying on the table in a room can be seen from all the parts or the rooms.
48) The two characteristic are :
- The left side of an object appears on the right side in the image whereas the right side of object appears on the left side of the image.
49) A periscope is a long, tubular device through which a person can see objects that are out of the direct line of sight.
50) The various uses of periscope are :
- A periscope is used to see over the heads of a crowd.
- A periscope is used by soldiers sitting in a trench.
- A periscope is used by a navy officer.
51) After giving the hair cut, hair dresser holds a small plane mirror behind the head. The light coming from Back of head is reflected by this small mirror to the big mirror, and the big mirror reflect the ‘reflected light’ again. So the person can watch the back hair of his head.
52) a> 2 , b> 7 , c> 1 , d> 5 , e> 3
54) Infinite number of Images.
55) Because the reflection of light.
56) When a white light go through a prism, it will be divide into seven colors.
57) Due to formation of a rainbow, we see the seven colors of the sunlight.
58) The process of splitting of white light into seven colors is called dispersion of light.
59) Three long and narrow strips mirror in a kaleidoscope.
60) By the focusing to the nearby objects, eye adjust itself to deal with light of varying intensity.
61) We cannot see our surrounding clearly when we enter a darkened cinema hall because then our pupil size is small so we cannot receive more light, but after few time, our pupil size increase so we can receive more light from surrounding.
62) The original eye lens can adjust its focal length by the help of eye muscles. But the ordinary convex lens made by the glass cannot adjust its focal length. This is the difference between eye lens and the ordinary convex lens made of glass.
63) a> Iris , b>
64) a> Cones , b> Rods. C> Cones
65) Rode are the rod-shaped cells and cones are the cone-shaped cells present in retina.
It is corrected by using spectacles containing concave lenses.
67) The medical condition in which the lens of eye of a person becomes progressively cloudy resulting in blurred vision is called cataract.
68) The persistence of vision means retention of a visual image for a short period of time after the removal of the stimulus that produced it the phenomenon that produces the illusion of movement when viewing motion pictures.
69) Care of our eyes :
- Wash our eyes at least twice a day with clean water.
- Always read by keeping the book at normal distance.
- Protect our eyes from injuries.
70) if it happens, we need to splash our eyes with a lot of clean water.
71) Carrot, Cod-liver oil, green vegetables, eggs etc.
72) Because it puts strain on the eyes and may cause headache.
73) An owl’s eye have more rode cells in retina than the eagle. That’s why owl can see well in the night.
74) The blind spot is a small area of the retina insensitive to light where the optic nerve leaves the eye.
75) The changes of sides of an object and its mirror image is called lateral inversion.
LONG ANSWER TYPE QUESTIONS Answer
76) The object which emit their own light are called luminous objects. Example : The sun, The lighted electric bulb.
The objects which do not emit their own light are called non-luminous object. Example : The moon, The earth.
77) The difference is regular reflection of light from a smooth surface but the diffuse reflection of light from a rough surface.
Mirror produce regular reflection of light, a sheet of paper produce diffuse reflection of light.