Ch 13 sound (science) keywords

 Ch–13

Light

Keywords / Homework

Incident Ray:

The light ray which strikes any surface is called the incident ray.

Reflected Ray:

The ray that comes back from the surface after reflection is known as the reflected ray.

Normal:

A line making an angle of 90° to the line representing the mirror at the point where the incident ray strikes the mirror. This line is known as the normal to the reflecting surface.

Angle of Incidence:

The angle between the normal and the incident ray is called the angle of incidence.

Angle of Reflection:

The angle between the normal and the reflected ray is known as the angle of reflection.

Lateral Inversion:

In the 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.

Diffused or Irregular Reflection:

When all the parallel rays reflected from a rough or irregular surface are not parallel, the reflection is known as diffused or irregular reflection.

Regular Reflection:

Reflection from a smooth surface like that of a mirror is called regular reflection.

Dispersion:

Splitting of light into its colours is known as dispersion of light.

Blind Spot:

At the junction of the optic nerve and the retina, there are no sensory cells, so no vision is possible at that spot.

Retina:

The lens focuses light on the back of the eye on a layer called the retina.

Iris:

Behind the cornea, a dark muscular structure is called the iris.

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