Advertisements
Advertisements
प्रश्न
Give two examples of periodic changes.
Advertisements
उत्तर
Swinging of a pendulum
Rising and setting of the sun.
APPEARS IN
संबंधित प्रश्न
Which of the following are chemical changes?
- Growth of a plant
- Rusting of iron
- Mixing of iron fillings and sand
- Cooking of food
- Digestion of food
- Freezing of water
- Burning of candle
Classify the changes involved in the following process as physical or chemical changes:
Photosynthesis
Write short answer.
Sublimation is classified as a physical change. Why ?
Solve this crossword by using the clues that follow-
Across
1. Energy in the form of sunlight is absorbed by the green plants in this process.
4. The reddish-brown substance formed over iron in the presence of oxygen and moisture.
5. This change is permanent and irreversible.
6. The process in which a solid directly changes into gaseous state.
Down
1 . It is the change that takes place in case of swinging pendulum of a clock. –
2. Occurrence of this is a non-periodic change as well as a natural change.
3. It is a physical change.
Which of the following are physical changes and which are chemical changes?
Burning of candle wax, Melting of candle wax, Mixing of iron filings and sand, Burning of wood, Breaking a piece of chalk, Burning a piece of paper, Cutting a piece of paper.
Given reason:
Burning of paper is a chemical change.
Give four reasons why the burning of a magnesium ribbon in the air is considered a chemical change.
Give a reason why – Addition of zinc nitrate to water is a physical change but, the addition of zinc to dilute nitric acid is a chemical change.
Select the chemical changes from the following list of changes
Butter turning rancid
Assertion: The explosion of fire cracker is a physical change.
Reason: A physical change is a reversible change.
