Class 10 Science Chapter 10 MCQ

The student sitting on the last bench can read the letters written on the blackboard but is not able to read the letters written in his book because he is suffering from hypermetropia or farsightedness. He can see distant objects clearly but cannot see nearby objects distinctly. Note: Hypermetropia may have blurred vision to a person when looking at objects close to them and clearer vision when looking at objects in the distance.

The sun appears red at sunset because, at that time, the sun is near the horizon and, therefore, sunlight has to travel through a greater thickness of the earth’s atmosphere.

Here, all the statements are correct. Hence, your answer will be option [D].

At noon the sun appears white because the light from the sun is directly overhead and travel relatively shorter distance. The sun appears white as only a little of the blue and violet colours are scattered.

The sky appears blue because some of the blue component of sunlight is scattered by the gas molecules (nitrogen and oxygen) present in the air.

The sun appears red at sunset not because of the atmospheric refraction of light but because of the scattering effect of light.

When the eye is looking at a distant object, the eye is said to be unaccommodated because it is the relaxed state of the eye.

Here, all the statements are correct. Hence, your answer will be option [D].

The clear sky appears blue is due to Rayleigh scattering of sunlight. The molecules in the air scatter blue light from the sun more than they scatter red light.

the whole purpose of using a concave lens here is to reduce the converging power of the eye-lens. The concave lens used here decreases the converging power of the eye-lens and helps in forming the image of distant object on the retina of the myopic eye.

The whole purpose of using a convex lens is to increase the converging power of the eye-lens. The convex lens used in spectacles increase the converging power of islands and helps in forming the image of a nearby object on the retina of the eye.

the propagation of light of different colours of white light in air or vacuum move with the same speed but different wavelengths and frequencies.

Here, all the statements are correct. Hence, your answer will be option [D].

The danger signals installed at the top of tall buildings are red in colour because among all other colours, red colour is scattered the least by smoke of fog. This is primarily because wavelength of red colour is the largest. Thus, it can be easily seen from a distance.

The bluish color of water in deep sea is due to scattering of light as the very fine particles in water scatter mainly blue light. The red, green, orange and yellow having longer wavelengths are absorbed more strongly by water then blue which has shorter wavelength. So, when white light from the sun enters the sea, it is mostly the blue that gets returned.

Actually, in refraction through a glass prism the emergent ray is deviated from its original direction by a certain angle. And we say that light rays get deviated on passing through a glass prism. Therefore, in refraction through a glass prism, the emergent ray is not parallel to the incident ray. Q.29. When light rays enter the eye, most of the refraction occurs at the

When the light rays enters the eye through a thin membrane, forms the transparent bulge on the front surface of the eyeball, called the cornea. Most of the refraction for the light rays entering the eye occurs at this outer surface of the cornea.

Here, all the statements are correct. Hence, your answer will be option [D].

The focal length of the eye lens increases when eye muscles relaxed and becomes thinner. The sharp image of the distant object is formed at the retina. This enables us to focus accurately on distant objects.

A person with myopia can see nearby objects clearly. While a person with hypermetropia can see distant objects clearly.

The nitrogen and oxygen gas molecules present in the atmosphere are smaller than the wavelength range of visible light. So, when light coming from the sun hits this very small air molecules, it behaves differently. Since, the different colours of white light have different wavelengths, so they are affected differently. The lower wavelengths lights (blues) are scattered much more by the air molecules but the higher wavelengths lights (reds) are scattered much less.

The term ‘accommodation’ as applied to the eye refers to its ability to vary the focal length of the lens.

The human eye possesses the power of accommodation to focus on objects at different distances.

The eye lens becomes thicker to focus on nearby objects and thinner to focus on distant objects.

Having two eyes gives a person a wider field of view.