Advertisements
Advertisements
प्रश्न
Change is the law of nature and occurs in our everyday life, at all times and in all places. Differentiate between the following change with a suitable example.
Desirable and undesirable change.
Advertisements
उत्तर
| Desirable change | Undesirable change |
| (i) Changes brought about by nature or man which produces – useful or good results. | (i) Changes brought about by nature or man which produces – useless or bad results. |
| (ii) Positive and advantageous nature. | (ii) Negative and detrimental nature. |
| (iii) Examples of a desirable change: Rain bringing water to the crops, change of milk to curd, ripening of fruits seedling into a plant. |
(iii) Examples of an undesirable change: Rain causing destruction by floods, milk turning sour on a hot day, rotting of fruits, cutting of trees. |
APPEARS IN
संबंधित प्रश्न
Write true or false for the statement
A natural change can also be a desirable change
Write short answer.
Give two examples of periodic changes
A physical change is temporary. Explain.
A burning candle shows both physical and chemical changes. Explain ?
State whether the following is physical or chemical changes.
shaping a piece of glass —
Tick (√) the correct alternative from the choice given for the following statement.
A substance which can not sublime is
Two chemical substances X and Y combine together to form a product P which contains both X and Y X + Y P
X and Y cannot be broken down into simpler substances by simple chemical reactions. Which of the following statements concerning X, Y and P are correct ?
- P is a compound
- X and Y are compounds
- X and Y are elements
- P has a fixed composition
Classify the following as a physical or a chemical change.
Burning of coal
Select the chemical changes from the following list of changes
Vaporisation of water into water vapour.
Assertion: Burning of wood log to charcoal is a physical change.
Reason: The products formed of burning a piece of wood can be easily converted back to wood log.
