Ans. The point of incidence is the point where the incident ray strikes the mirror.
Ans. Moon receives light from the sun and reflects it. That’s how we see the moon.
Ans. The two types of reflection of light are Regular reflection of light and Diffused reflection of light.
Ans. The ray that comes back from the surface after reflection is known as the reflected ray.
Ans. The angle between the normal and the reflected ray is known as the angle of reflection (∠r).
Ans. Periscopes are used in submarines, tanks and also by soldiers in bunkers to see things outside.
Ans. Designers of wallpapers and fabrics and artists use kaleidoscopes to get ideas for new patterns.
Ans. The objects which emit their own light are known as luminous objects. Example: sun, fire, flame of a candle and an electric lamp.
Ans. The objects which shine in the light of other objects are called illuminated objects. Example: moon.
Ans. Wooden screen are opaque object that does not allow light to pass through it. Thus we are not able to see through it.
Ans. At the junction of the optic nerve and the retina, there are no sensory cells, so no vision is possible at that spot. This is called the blind spot.
Ans. The image formed by a plane mirror is always virtual, upright, and of the same shape and size as the object it is reflecting.
Ans. In an image formed by a mirror the left of the object appears on the right and the right appears on the left. This is known as lateral inversion.
Ans. The most comfortable distance at which one can read with a normal eye is about 25 cm.
Ans. Splitting of light into its colours is known as dispersion of light. Rainbow is a natural phenomenon showing dispersion.
Ans. The angle of reflection will be 40 degree. This is by the law of reflection that angle of incidence is equal to the angle of reflection.
Ans. Laser light is harmful for the human eye because it can injure the retina. Hence, it is advisable not to look at a laser beam directly.
Ans. The iris is the part of that eye which gives it its distinctive colour. When we say that a person has green eyes, we refer actually to the colour of the iris.
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