Class 10 Science - Chapter The Human Eye and the Colourful World NCERT Solutions | A person with a myopic eye cannot see ob

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

Why do stars twinkle?

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.

Explain why the planets do not twinkle.

What is meant by power of accommodation of the eye?

The human eye forms the image of an object at its

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

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.

Why does the sky appear dark instead of blue to an astronaut?

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.

Why does micelle formation take place when soap is added to water? Will a micelle be formed in other solvents such as ethanol also?

In the electrolytic refining of a metal M, what would you take as the anode, the cathode and the electrolyte?

Redraw the circuit of Question 1, putting in an ammeter to measure the current through the resistors and a voltmeter to measure the potential difference across the 12 Ω resistor. What would be the readings in the ammeter and the voltmeter?

What is biological magnification? Will the levels of this magnification be different at different levels of the ecosystem?

How are fats digested in our bodies? Where does this process take place?

Why are coils of electric toasters and electric irons made of an alloy rather than a pure metal?

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

Outline a project which aims to find the dominant coat colour in dogs.

Why should curd and sour substances not be kept in brass and copper vessels?

Let the resistance of an electrical component remains constant while the potential difference across the two ends of the component decreases to half of its former value. What change will occur in the current through it?