(4) Multiple reflection
(7) Ciliary, thickness
(8) Near point
(12) Deviated and dispersed
(15) Rectangular slab
When the incident and reflected rays do not actually meet at the image and the image can not be formed on a screen then this is virtual image.
The image formed by plane mirror is erect, virtual same size as the object, laterally inverted.
From a submarine under the sea, a sailor can see objects and enemy ships on the surface of the sea by using a periscope.
Number of images formed is given by the formula –
n = 360/0 -1
n = 360/30 -1
n = 12 – 1
n = 11 images
The convex mirror is bulging out from the middle while the concave lens bulging out from the edges.
Aperture of lens is a point from where the reflection of light takes place.
Vitamin A helps to improve eyesight so we should have vitamin A rich diet which includes pumpkin, mangoes, carrot, yam, dairy products, eggs and fish.
Refraction is caused by the change of speed of light when it passes from one medium to another.
The air in the atmosphere consists of different layers of different densitiesThe density is maximum near the surface of EarthRefraction takes place at the surface of each layerBecause of atmosphere refraction all stars except those directly overhead, appeared slightly above the horizon than they really are.
The least distance at which the eye can see an object clearly is called the near point of the eyeWhile the far point of the eye is the maximum distance at which it can see clearlyFor a normal eye, it is at infinity.
When light ray strike on opaque surface and rebound into the same medium, reflection occursWhile Refraction occurs when a ray of light passes from one transparent to another having different densities.
(a) In the case of concave lens the rays of light do not actually meet but appear to diverge from a point called principle focusIt has the property of bending a ray of light passing through it outwards.
(b) Because beam of light after passing through a prison formed a bend of seven colours called spectrum.
(c)We are able to see an image only if it is formed on the retinaIf the image is focused in form or behind the retina, the image appeared to be blurred.
A converging (convex) lens is thick in the middle and become thinner at the edges.
A converging lens bends a ray of light passing through it inwards.
A diverging (concave) lens is thin at the middle and thicker at the edges.
Diverging lens bends a ray of light passing through it outwards.
A pencil dipped in water appears bent at the surface of water because of refraction.
This light class 8 questions and answers is prepared keeping in mind the latest syllabus of CBSE . This has been designed in a way to improve the academic performance of the students. If you find mistakes , please do provide the feedback on the mail.