NCERT Solutions for Class 8th Science
Chapter 16. Light
- Light is reflected from all surfaces.
- The light ray, which strikes any surface, is called the incident ray.
- The ray that comes back from the surface after reflection is known as the reflected ray.
- Reflection from a smooth surface like that of a mirror is called regular reflection.
- When all parallel rays reflected from a plane surface are not parallel, the reflection is known as diffused or irregular reflection.
- The angle between the normal and incident ray is called the angle of incidence (∠i).
- The angle between the normal and the reflected ray is known as the angle of reflection (∠r).
- The incident ray, the normal at the point of incidence and the reflected ray all lie in the same plane.
- The angle of incidence is always equal to the angle of reflection. This is known as the law of reflection.
- 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.
- The objects which shine in the light of other objects are called illuminated objects.
- The objects which emit their own light are known as luminous objects.
- Splitting of light into its colours is known as dispersion of light.
- Outer coat of the eye is white. Its transparent front part is called cornea.
- Behind the cornea a dark muscular structure called iris.
- The size of the pupil is controlled by the iris.
- The lens focuses light on the back of the eye, on a layer called retina.
- 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.
- A normal eye can see nearby and distant objects clearly.
- The most popular resource for visually challenged persons is known as Braille.
- Sunlight, called white light but consists of seven