NCERT Science Class 10 Chapter 11 the Human Eye and the Colourful World CBSE Board Sample Problems Very Short Answer
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Question
What is the nature of image formed on the retina of the eye?
Solution
Real and inverted.
Question
State one effect produced by the scattering of light by the atmosphere?
Solution
Tyndall effect.
Question
Define power of accommodation?
Solution
The ability of the eye lens to adjust its focal length is called power of accommodation.
Question
What is the cause of dispersion of light on passing through a prism?
Solution
The refractive index of the material of a prism is different for different colours of light as different colours have different speed in the material of a prism
Question
What is the far point and near point of human eye with normal vision?
Solution
The far point is infinity and near point is about 25 cm of the normal human eye.
Question
An Astronaut in space finds sky to be dark. Explain reason for this observation.
Solution
In space there is no atmosphere, so there is no scattering hence the sky appears dark/black.
Question
What is meant by scattering of light?
Solution
Scattering of light is the phenomenon due to which light gets deflected by the atoms, molecules or particles of the medium when light falls on them.
Question
Which lens is used to correct hypermetropia?
Solution
Convex lens
Question
Which phenomenon is responsible for making the path of light visible?
Solution
Tyndall effect
Question
Name the components of white light which deviates the least and the components that deviates the most while passing through a prism.
Solution
Least: Red
Most: Violet
Question
What is the smallest distance up to which an eye can see without strain?
Solution
Near point or 25 cm.
Question
A person is advised to wear spectacles with concave lens. What type of defect of vision is he suffering from?
Solution
Near-Sighted ness/Myopia
Question
Which defect of an eye can be corrected by using concave lens?
Solution
Myopia
Question
The following questions consists of two statements - Assertion (A) and Reason (R).
Answer these questions selecting the appropriate option given below:
(a) Both A and R are true and R is correct explanation of A.
(b) Both A and R are true and R is not correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true
Assertion (A): The sky looks dark and black instead of blue in outer space.
Reason (R): No atmosphere containing air in the outer space to scatter sunlight.
Solution
(a)
Question
The following questions consists of two statements - Assertion (A) and Reason (R).
Answer these questions selecting the appropriate option given below:
(a) Both A and R are true and R is correct explanation of A.
(b) Both A and R are true and R is not correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true
Assertion (A): Danger signals are made of red colour.
Reason(R). : Velocity of red light is maximum in air, so signals are visible in dark.
Solution
(C)
Question
Calculate maximum power of accommodation of a person having normal vision. (1)
Solution
For a person having normal vision, Least distance of distinct vision is d=25cm
Therefore, maximum power of accommodation,
Dioptre
(1)