Page 271 Question 1. What changes can you make in your habits to become more environment friendly? Answer 1 (i) By minimising the water usage and avoiding its wastage. (ii) Saving power by switching off unnecessary lights and fans. (iii) Avoiding wastage of food by consuming it rationally as per our needs. (iv) Walking down or use bi-cycle for going to nearby … [Read more...] about Chapter 16 Sustainable Management of Resources
Science
Chapter 15 Our Environment
Page 260 Question 1. What are trophic levels? Give an example of a food chain and state the different trophic levels in it. Answer 1 Trophic levels in a food chain represent various steps where transfer of food energy takes place. Example: A simple food chain found in a grassland is given below: Grass → Insects → Frogs → Snakes (i) Grass → I trophic level … [Read more...] about Chapter 15 Our Environment
Chapter 14 Sources of Energy
Page 243 Question 1. What is a good source of energy? Answer 1 A good source of energy should have the following qualities: (i) It should be easily available. (ii) It does not produce pollution. (iii) It should be renewable and environment friendly. (iv) It should produce large amount of heat per unit volume/mass. (v) It should be easy to store and … [Read more...] about Chapter 14 Sources of Energy
Chapter 13 Magnetic Effects of Electric Current
Page 224 Question 1. Why does a compass needle get deflected when brought near a bar magnet? Answer 1 A compass needle is a small bar magnet. When it is brought near a bar magnet, its magnetic field lines interact with that of the bar magnet. Hence, a compass needle shows a deflection when brought near the bar magnet. Page 228 Question 1. Draw magnetic field lines … [Read more...] about Chapter 13 Magnetic Effects of Electric Current
Chapter 11 The Human Eye and the Colourful World
Page 190 Question 1. What is meant by power of accommodation of the eye? Answer 1 When the ciliary muscles are relaxed, the eye lens becomes thin, the focal length increases and the distant objects are clearly visible to the eyes. To see the nearby objects clearly, the ciliary muscles contract making the eye lens thicker. Thus, the focal length of the eye lens … [Read more...] about Chapter 11 The Human Eye and the Colourful World