1- What is light?
Ans:- Light is a form
of energy that makes everything visible. It always travels in straight
direction.
2- What is source of
light?
Ans:- All the objects
that gives off light is called source of light.
3- How many types of source of light?
Ans:- There are two
types of source of light.
1- natural source of
light
2- artificial source
of light
4- What are natural sources of light? Give
example.
Ans:- Those source of
light that are made by nature are called natural source of light.
Ex:- sun, star,
glow-worms etc.
5- What are artificial sources of light?
Give example.
Ans:- Those source of
light that are made by humans are called artificial source of light.
Ex:- candle, electric
bulb etc.
6- How can we see things?
Ans:- When light from
the source of light falls on a object, than a part of light bounced off. When
this bounced light falls on our eyes, then we can see the object.
7- Write three properties of light.
Ans:- The three
properties of light are
1- Light travels from
one place to another.
2- Light travels in
straight line.
3- Light is made up of
seven colours.
8- What are rays of light?
Ans:- The thin beams
of light are called rays of light.
9- What is rectilinear propagation of
light?
Ans:- The propagation
of light in a straight line is known as rectilinear propagation of light.
10- How many types of objects based on
their behaviour towards light?
Ans:- There are three
types of objects based on their behaviour towards light.
1- Transparent
2- Translucent
3- opaque
11- What are transparent objects?
Ans:- Materials that
allow almost all light to pass through them are called transparent objects.
Ex:- air, pure water,
transparent plastics etc.
12- What are translucent objects?
Ans:- Materials that
allow only some light to pass through but not enough to see clearly through
them are called translucent objects.
Ex:- butter paper,
frosted glass etc.
13- What are opaque objects?
Ans:- Materials that
do not allow any light to pass through them are called opaque materials.
Ex:- metal, cardboard,
rubber etc.
14- What is shadow?
Ans:- A shadow is formed when something blocks the path of light. A shadow is always black in colour.
15- Write four things that is necessary
for the formation of shadow.
Ans:- The four things
that is necessary for the formation of shadow are
1- A source of light
2- Something that
blocks the light coming from the source.
3- A surface to form
shadow on
4-A shadow always forms on the opposite side of the source of light.
16- Write short notes about the size of
the shadow
Ans:- The size of the
shadow depends on the distance between the source of light and the object.
1- When the distance
between the source of light and the object is more than the size of shadow is
smaller.
2- When the
distance between the source of light and the object is less than the size of
shadow is bigger.
17- What is eclipse?
Ans:- An eclipse occurs when a celestial object moves directly into the shadow of another celestial object.
18- How many types of eclipse?
Ans:- There are two
types of eclipse.
1- lunar eclipse
2- solar eclipse
19- What is lunar eclipse?
Ans:- A lunar eclipse occurs when the sun, earth and moon are in a straight line. It occurs when earth comes between sun and moon than the shadow of earth falls on moon. The lunar eclipse always occurs on a full moon light.
20- How many types of lunar eclipse?
Ans:- There are two
types of lunar eclipse.
1- Total lunar eclipse
2- Partial lunar eclipse
21- What is total lunar eclipse?
Ans:- The total lunar eclipse occurs when earth's shadow covers the moon completely.
22- What is partial lunar eclipse?
Ans:-The partial lunar
eclipse occurs when earth's shadow covers the moon partially.
23- What is solar eclipse?
Ans:- A solar eclipse
occurs when the sun, earth and moon are in a straight line. It occurs when moon
comes between sun and earth than the shadow of moon falls on earth. The solar
eclipse always occurs on a new moon day.
24- How many types of solar eclipse?
Ans:- There are two
types of solar eclipse.
1- Total solar eclipse
2- Partial solar
eclipse
25- What is total solar eclipse?
Ans:- An eclipse of the sun in which the moon completely hides the solar surface and thereby cuts off all direct rays of sunlight from the observer is called total solar eclipse.
26- What is partial solar eclipse?
Ans:- An eclipse of the sun in which the moon does not completely hides the solar surface so that some direct rays of sunlight reach the observer is called partial solar eclipse.
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