Figure On what basis are the objects mentioned here classified? (a) non-METALS and metals (b) non-MAGNETIC and magnetic (c) inflammable and non-flammable (d) all the above ANSWER: (a) non-metals and metals. Air, wood and impure water are non-metals, whereas copper, aluminium and silver are metals.   Page No 53: Question 2: In which of these groups are all the items transparent? (a) water, mirror, spectacles (b) water, air, spectacles (c) mirror, air, STEEL plate (d) wood, steel plate, brick ANSWER: (b) water, air, spectacles Water, air and spectacles are transparent as they allow light to pass through them completely. Page No 53: Question 3: Which of the following is elastic, opaque and inedible? (a) GOLD chain (b) rubber (c) chapatti dough (d) chewing gum ANSWER: (b) rubber Rubber is elastic, opaque and is not fit for eating. Page No 53: Question 4: Float and sink; transparent and opaque; lustrous and dull; conductor and insulator; hard and soft: (a) all are properties of solids. (b) all are pairs of opposites. (c) both a and b (d) none of the above ANSWER: (b) all are pairs of opposites All of the mentioned items are pairs of opposite traits. Page No 53: Question 5: Rita wrote down some properties of copper, aluminium and iron. Which of them are correct. (a) All are metals. (b) All are good conductors of heat and electricity. (c) All are ductile. (d) All of the above are correct. ANSWER: (d) All of the above are correct Copper, aluminium and iron are metals. All metals are ductile and are good conductors of heat and electricity. Page No 54: Question 6: Study the flow chart GIVEN below and identify the objects A, B, C and D. (a) A-petrol; B-water; C-wax; D-silver (b) A-petrol; B-water; C-stone; D-iron (c) A-water; B-petrol; C-wax; D-silver (d) A-petrol; B-shampoo; C-silver; D-wood Figure ANSWER: (b) A-petrol; B-water; C-stone; D-iron Petrol is flammable, water is a liquid, stone is hard and iron is a metal. Page No 54: Question 7: IExplanation: