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.

the space between cornea and eye lens is filled with a watery liquid called “aqueous humor”. And the space between eye lens and retina is filled with transparent jelly like substance called vitreous humour which supports the back of the eye.

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.

Rainbow is caused by dispersion, refraction and internal reflection of sunlight by tiny water droplets, present in the atmosphere and always formed in a direction opposite to that of the sun. The water droplets act like a small prism. They refract and disperse the incident sunlight, then reflect it internally and finally refract it again when it comes out of the raindrop.

The cone shaped cells of the retina make us to see colours and also make us distinguish between various colours. Cone cells of the retina function only in bright light. The cones do not function in dim light. This is why when it is getting dark at night, it becomes impossible to see colours of cars on the road.

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

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

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.

As the person has the eye defect, myopia, therefore, a concave lens has to be used whose focal length will be, f = – 2 m (using sign convention). Thus, Power, P = 1/f (where, f is focal length in metre) = 1/- 2 = -0.5 D

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.

Stars twinkle because they are far away. The planets do not twinkle at night because they are nearer to the earth.

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

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.

Predators have both the eyes at the front of their heads so that they can judge the distance of their prey accurately.

The reddish appearance of the sun at sunrise or sunset is due to least scattering of red light. The red light has the maximum wavelength. The rays of light have to travel a larger part of the atmosphere.

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.

If a man driving a car can see a distant road sign distinctly but cannot read the odometer on the dashboard of the car clearly, it suggests that the near point of his eyes has receded.

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

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 thickness of the eye lens is increased to focus the image of a nearby object on the retina of the eye.

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

As the far point of the eye is closer to him than normal, he can see nearby objects, but not distant objects, clearly.

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