Class 10 Science Chapter 11 MCQ with Answers for 2020-2021
| Class: 10 | Science |
| Chapter: 11 | Human Eye and Colourful World |
| Contents: | MCQ Online Tests with Explanation and Answers |
Class 10 Science Chapter 11 MCQ Online Test for 2020-21
Class 10 Science Chapter 11 MCQ Online tests with solutions and explanation are given below. All the questions are important for exams. After completing Chapter 11 from NCERT Textbook, these questions are helpful for the preparation of exams in less time.
Q1
Read the following sentences carefully, and choose the incorrect one:
[A]. The human eye works on the refraction of light
[B]. The eye lens is a convex lens made of a transparent, soft and flexible material like a jelly made of proteins.
[C]. The focal length of a lens can be changed by changing its shape by the action of ciliary muscles.
[D]. All the above
Answer: Option D
Explanation: Here, all the statements are correct. Hence, your answer will be option [D].
Q2
The sky appears blue because some of the blue component of sunlight is scattered by:
[A]. Gas molecules present in air
[B]. Dust particles present in air
[C]. Water droplets suspended in air
[D]. Soot particles present in air
Answer: Option A
Explanation: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.
Q3
In the last year board examination, Rahul were asked a question where he had to choose the statement which was/were incorrect? Will you be able to answer this question?
[A]. Rods are the rod-shaped cells present in the retina of an eye which are sensitive to dim light.
[B]. Cone are the cone shaped cells present in the retina of an eye which are sensitive to bright light or normal light.
[C]. The cones easily work on in dim light but not bright light.
[D]. Normal eye can see the distant objects as well as the nearby objects clearly due to its power of accommodation.
Answer: Option C
Explanation: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.
Q4
Badal appeared in class test but he confused to know the incorrect statement. Would you help him to know that?
[A]. Myopia is that defect of vision due to which a person cannot see the distant object clearly.
[B]. The far point of an eye suffering from myopia is less than infinity.
[C]. Myopia is corrected by using spectacles containing concave lenses.
[D]. The whole purpose of using a concave lens here is to increasing the converging power of the eye-lens.
Answer: Option D
Explanation: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.
Q5
The bluish colour of water in deep sea is due to
[A]. The presence of algae and other plants found in water
[B]. Reflection of sky in water
[C]. Scattering of light
[D]. Absorption of light by the sea
Answer: Option C
Explanation: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.
Q6
The animals called predators have:
[A]. Both the eyes on the sides
[B]. One eye on the side and one at the front
[C]. One eye on the front and one at the back
[D]. Both the eyes at the front
Answer: Option D
Explanation:Predators have both the eyes at the front of their heads so that they can judge the distance of their prey accurately.
Q7
A man driving a car can read a distant road sign clearly but finds difficulty in reading the odometer on the dashboard of the car. Which of the following statement is correct about this man?
[A]. The near point of his eyes has receded away.
[B]. The near point of his eyes has come closer to him.
[C]. The far point of his eyes has receded away.
[D]. The far point of his eyes has come closer to him.
Answer: Option A
Explanation: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.
Q8
The focal length of the eye lens increases when eye muscles
[A]. Are relaxed and lens become thinner
[B]
[C]
[D]
[B]. Contract and lens becomes thicker
[C]. Are relaxed and lens becomes thicker
[D]. Contract and lens becomes thinner
Answer: Option A
Explanation: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.
Q9
How does the eye change in order to focus on near or distant objects?
[A]. The lens moves in or out
[B]. The retina moves in or out
[C]. The lens becomes thicker or thinner
[D]. The pupil gets larger or smaller
Answer: Option C
Explanation:The eye lens becomes thicker to focus on nearby objects and thinner to focus on distant objects.
Q10
A student sitting on the last bench in the class cannot read the writing on the blackboard clearly but he can read the book lying on his desk clearly. Which of the following statement is correct about the student?
[A]. The near point of his eyes has receded away.
[B]. The near point of his eyes has come close to him.
[C]. The far point of his eyes has receded away.
[D]. The far point of his eyes has come closer to him.
Answer: Option D
Explanation:As the far point of the eye is closer to him than normal, he can see nearby objects, but not distant objects, clearly.
What is the function of Iris?
Iris is a dark muscular diaphragm that controls the size of the pupil.
What is meant by accommodation of eye?
The ability of the eye lens to adjust its focal length is called accommodation.
Why do stars twinkle?
The twinkling of a star is due to atmospheric refraction of starlight. The starlight, on entering the earth’s atmosphere, undergoes refraction continuously before it reaches the earth.This makes continuously change in star’s position and we see the twinkling of stars.
Why does sky apear blue in colour?
The molecules of air and other fine particles in the atmosphere have size smaller than the wavelength of visible light. These are more effective in scattering light of shorter wavelengths at the blue end than light of longer wavelengths at the red end. When sunlight passes through the atmosphere, the fine particles in air scatter the blue colour (shorter wavelengths) more strongly than red. The scattered blue light enters our eyes and we see blue sky.
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