Question

Formation of clouds a. Bacteria Rusting of iron b. Condensation Curdling of milk c. Fermentation Freezing of water d. Chemical change Glucose to alcohol e. Physical change .IV. State true or false. A metal coaster becoming red hot on heating is a reversible change. __________ Changes can be caused by applying pressure. __________ Occurrence of tsunami is a desirable change. __________ Weathering of rocks is a reversible change. __________ New substances are formed in a physical change. __________ V. Choose the odd one out:- a. Evaporation b. Condensation c. Refining d. Melting a. Folding of paper b. Burning of candle c. Souring of milk d. Sublimation a. Growth of plants b. Cutting of trees c. Ripening of fruits d. Stretching of rubber band a. Expansion b. Contraction c. Freezing d. Rusting a. Making coffee b. Roasting c. Melting of chocolate d. Baking cake V. Write the type of change occurs in the following processes:- Knitting of sweater _____________________________ Digestion of food _____________________________ Cutting of vegetables _____________________________ Rusting of iron _____________________________ Expansion in solids _____________________________ Deflating of a cycle tyre tube ______________________________ Rusting of iron _____________________________ Inflating a balloon ` _____________________________ Boiling of an egg _____________________________ Cutting vegetables _____________________________ VI. Answer the following:- Give two examples of physical changes which are irreversible also. ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ Why tearing of paper is a physical change? __________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ ______________________________________________________________________________ Name one metal which expands on heating and contracts on cooling _________________________________________________________________________________________________________________________________________________________________________________________ Name one drink which is formed due to fermentation ._______________________________________________________________________________________________________________________________________________ An irreversible change caused due to heating __________________________________________________________________________________________________________________________________________________ Why is mercury used in clinical thermometers? _______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Why is a gap left between rails in railway tracks? _______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Give two examples of physical changes which are reversible. _______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Give two examples of changes which are useful to us. _______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Write two changes which are undesirable. __________________________________________________________________________________________________________________________________________________________________________________________ Why are wires carrying electricity not strung tightly? ____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Answer 1

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Explanation:

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