Class 10 Science - Chapter The Human Eye and the Colourful World NCERT Solutions | What happens to the image distance in th

What is the far point and near point of the human eye with normal vision?

Make a diagram to show how hypermetropia is corrected. The near point of a hypermetropic eye is 1 m. What is the power of the lens required to correct this defect? Assume that the near point of the normal eye is 25 cm.

Why do stars twinkle?

Explain why the planets do not twinkle.

The human eye forms the image of an object at its

(a) cornea.          (b) iris.          (c) pupil.          (d) retina.

What is meant by power of accommodation of the eye?

A student has difficulty reading the blackboard while sitting in the last row. What could be the defect the child is suffering from? How can it be corrected?

The least distance of distinct vision for a young adult with normal vision is about

(a) 25 m.          (b) 2.5 cm.          (c) 25 cm.          (d) 2.5 m.

A person with a myopic eye cannot see objects beyond 1.2 m distinctly. What should be the type of the corrective lens used to restore proper vision?

The change in focal length of an eye lens is caused by the action of the

         (a) pupil.                        (b) retina.
         (c) ciliary muscles.        (d) iris.

Did Döbereiner’s triads also exist in the columns of Newlands’ Octaves? Compare and find out.

What is a good source of energy?

Why is diffusion insufficient to meet the oxygen requirements of multi-cellular organisms like humans?

What are trophic levels? Give an example of a food chain and state the different trophic levels in it.

What changes can you make in your habits to become more environment-friendly?

What is the difference between a reflex action and walking?

What is the importance of DNA copying in reproduction?

If a trait A exists in 10% of a population of an asexually reproducing species and a trait B exists in 60% of the same population, which trait is likely to have arisen earlier?

Why should a magnesium ribbon be cleared before burning in air?

Define the principal focus of a concave mirror.

An atom has electronic configuration 2, 8, 7.

   (a)  What is the atomic number of this element?
   (b)  To which of the following elements would it be chemically similar? (Atomic numbers are given in parentheses.)
          N(7)      F(9)      P(15)      Ar(18)

In evolutionary terms, can we say which among bacteria, spiders, fish and chimpanzees have a ‘better’ body design? Why or why not?

Find out about the traditional systems of water harvesting/management in your region.

Which one of the following materials cannot be used to make a lens?

(a) Water        (b) Glass        (c) Plastic        (d) Clay

A battery of 9 V is connected in series with resistors of 0.2 Ω, 0.3 Ω, 0.4 Ω , 0.5 Ω and 12 Ω, respectively. How much current would flow through the 12 Ω resistor?

How could the Modern Periodic Table remove various anomalies of Mendeléev’s Periodic Table?

How are involuntary actions and reflex actions different from each other?

Can you think of reasons why more complex organisms cannot give rise to new individuals through regeneration?

Explain the underlying principle and working of an electric generator by drawing a labelled diagram. What is the function of brushes?

How does reproduction help in providing stability to populations of species?