Q2. Fill in the blanks :
1. The point at which the incident ray falls on the mirror is called___________________
2. If a ray of light is incident on a plane mirror at an angle of 30 with the normal,its angle of reflection is _______________.
3. If a ray of light is incident normally on a mirror, angle i = __________ and angle r = ________________
4. The image of our face in a plane mirror is an example of ___________ image.
5. The distance of the image behind the plane mirror is _________ to the distance of the object in front of it.
6.. The presence of __________________ cells on the retina helps us to see in dimlight. 7. The coned shaped cells of our retina respond to _____________
8. Due to the absence or insufficient number of ____________ cells a personbecomes colour blind.
9. Owls and bats are able to see at night due to the presence of ______________cells in their retina
Answers
ღ Required Answer :-
1. The point at which the incident ray falls on the mirror is called point of incidence.
ღ The Explanation :-
When a ray of light is incident on a plane mirror, it is known as an incident ray and it falls on the mirror at a point known as the point of incidence.
ღ Required Answer :-
2. If a ray of light is incident on a plane mirror at an angle of 30 with the normal,its angle of reflection is 60°.
ღ The Explanation :-
The incident ray will have an angle of reflection of 30 degrees (made with a surface normal to the mirror surface). The reflected ray will make an angle of 60 degrees (90 - 30 degrees) with the mirror surface
ღ Required Answer :-
3. If a ray of light is incident normally on a mirror, angle i = r and angle r = i1.
ღ The Explanation :-
In reflection, angle of incident is always equal to angle of reflection.
ღ Required Answer :-
4. The image of our face in a plane mirror is an example of virtual image.
ღ The Explanation :-
The image formed by the plane mirror is always said to be a virtual image. And these virtual images have the same size and shape as the object is reflecting.
ღ Required Answer :-
5. The distance of the image behind the plane mirror is equal to the distance of the object in front of it.
ღ The Explanation :-
For plane mirrors, the object distance (is equal to the image distance. That is the image is the same distance behind the mirror as the object is in front of the mirror. If you stand a distance of 2 meters from a plane mirror, you must look at a location 2 meters behind the mirror in order to view your image.
ღ Required Answer :-
6. The presence of cone cells on the retina helps us to see in dim light.
ღ The Explanation :-
Cone cells, or cones, are photoreceptor cells in the retinas of vertebrate eyes including the human eye. They respond differently to light of different wavelengths, and are thus responsible for color vision, and function best in relatively bright light, as opposed to rod cells, which work better in dim light.
ღ Required Answer :-
7. The cone shaped cells of our retina respond to light.
ღ The Explanation :-
They respond differently to light of different wavelengths, and are thus responsible for color vision, and function best in relatively bright light, as opposed to rod cells, which work better in dim light.
ღ Required Answer :-
8. Due to the absence or insufficient number of cone cells a person becomes colour blind.
ღ The Explanation :-
Cone cells, or cones, are photoreceptor cells in the retinas of vertebrate eyes including the human eye. They respond differently to light of different wavelengths, and are thus responsible for color vision, and function best in relatively bright light, as opposed to rod cells, which work better in dim light.
ღ Required Answer :-
9. Owls and bats are able to see at night due to the presence of rod cells in their retina.
ღ The Explanation :-
Seeing well in the dark is the major function of an owl's eyes. Eye size is very important for seeing at night. Because an owl's eyes are so large, they have a large surface area to collect light. The light hits specialized cells in the eye that help animals see in low light levels. These cells are called rod cells. Owls have many more rod cells than other animals.
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