PHYSICS [3 Mark Question Answer]

An annular solar eclipse occurs when only the tip of the umbra of the moon falls on the earth. From point D, the sun will appear to be completely obstructed by the moon, only the outer rim of the sun, called the corona, is then visible for a very short time which is known as the diamond ring. The formation of the annular solar eclipse is shown below.

On a certain moon’s day, the moon happens to come in between the sun and the earth. They come in a straight line. In such a situation, the moon being smaller in size casts its shadow only on a limited region on the earth. In these regions of the earth, the solar eclipse occurs.

A lunar eclipse occurs when the earth comes in between the sun and moon and casts its shadow on the moon. On a full moon night, the moon rises in the east after sunsets in the west. On such a night, the sun and moon are on the opposite sides of the earth. The shadow of the earth falls on the surface of the moon therefore moon's not visible to us. This is a lunar eclipse as shown in the figure.

If you move the screen away from the object, the shadow increases in size. Formation of umbra and penumbra both.

Umbra

1. It is the portion of shadow where no light reaches from the source of light due to the opaque object.
2. It is completely dark.

Penumbra
It is the portion of shadow where a portion of light from the source of light reaches the shadow even in the presence of the opaque object in between them.
It is not completely dark but is dim (or less bright).

If we move the screen away from the object, the shadow increases in size.

The pinhole camera is a simple application of the rectilinear propagation of light.

The light traveling in any one direction in a straight line is called a ray of light.

A group of light rays given out from a source is called a beam of light

A point source of light is obtained either by placing a screen having a fine hole, in front of die luminous body, or by placing the luminous body inside a box having a fine hole on one of its sides.

1. Transparent objects:Those objects through which light can pass easily are called transparent objects. e.g. Water, glass, air.
2. Translucent object:The object through which light can pass partially are called translucent object, e.g. tracing paper, waxed paper.
3. Opaque object: The objects which do not allow the light to pass through are called opaque objects, e.g. wood.