NCERT Class 8 solutions are created by proficient teachers having great experience in explaining these questions. Going through these answers will make you grasp the concept of Light quickly and easily. Let’s dive into class 8 science chapter 16 answers to crucial questions:
1. What makes Light visible?
The only electromagnetic waves we can see are the lightwaves. The electromagnetic radiation visible to the human eye in this range of wavelengths is called visible light.
When all electromagnetic waves are visible together, they form white light, and when it shines through a prism, it is broken into the colours of the visible light spectrum. Typically, the human eye will respond to wavelengths ranging from 380 to 750 nanometers.
While we can see the light, it gets reflected from our eyes and makes the object visible.
2. What do Laws of reflection State?
The laws of reflection can be started as follows:
a) The angle of reflection and the angle of incidence are always equal.
b) The reflected ray, the incident ray, and the normal to the reflective surface at the point of incidence all come on the same plane.
3. Regular Reflection Vs Diffuse reflection
A. Regular Reflection
Regular reflection, also known as specular reflection, is the mirror-like reflection of the waves. An example of regular reflection is the reflection by the plane mirror.
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It occurs when the surface is smooth and polished.
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All the reflected rays are parallel.
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These rays travel in one direction.
B. Diffuse reflection
Diffuse reflection is the reflection of light from a surface scattered at many angles rather than just in one direction, unlike specular reflection. An example of diffused reflection is the reflection by the road surface.
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It occurs when the surface is rough.
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All the reflected rays are not parallel.
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These rays are scattered in different directions.
In any instance, diffuse reflection does not mean the failure of laws of reflection.
4. Reflection of Reflected Light
When a ray of light falls on an object, be it smooth, shiny, polished, or rough, some proportion of light bounces back to our eyes. It is known as Reflection of Light or simply Reflection. For instance, when the light is reflected by a mirror or twinkling stars.
The answer is yes; the reflected light can be reflected again when the two mirrors are placed opposite to each other. The first reflection occurs when the light falls onto the surface of the first mirror. However, when the first mirror's reflection falls onto the surface of the second mirror, another reflection is visible from the second mirror.
5. Sunlight: White or coloured?
The Sunrays are white and form a mixture of 7 colours, also known as white light. These 7 colours are the same we see in a rainbow, i.e., (VIBGYOR) Violet, Indigo, Blue, Green, Yellow, Orange, and Red.
The Sun might also appear changing its colours during the day, solely because of a phenomenon called dispersion of light.
6. Inside the eye
The eye is filled with a clear gel liquid called the vitreous. The inside lining of the eye helps convert light into electrical impulses, covered by special light-sensing cells, collectively called the retina. Our optic nerve carries these impulses to the brain, behind the eye.
7. Caring for the eye
The eye is the most sensitive organ in our body. It is considered the biggest gift of nature that enables us to see the beautiful world. So, they must serve us for our entire life. Isn't it? But how to take care of our eyes and ensure their protection.
It is very simple. Always keep your eyes away from sharp objects, and avoid damaging them by playing carelessly.
Check out the other critical points explaining how to take care of your eyes:
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Avoid reading in very dim or bright light.
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Visit an eye specialist frequently.
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One should never see the Sun and avoid direct sunlight exposure to the eye.
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A minimum distance of 25 cm between the book and the eyes is important.
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If any tiny particle or dust enters your eye, never rub it. Go and clean your eyes immediately with regular water.
Maths (16)