7Class Science Changes around Us

Which of the property of iron is NOT a physical poperty?

• Electrical conductivity
• Magnetic property
• Good conductor of heat
• Reaction with moiture to get rusted

1. Bacteria digests animal waste and produces biogas.

2.Biogas is then burnt as fuel.

Choose the correct statement.

• Bacteria digests animal waste and produces biogas is chemical change

• The biogas is then burnt as fuel is chemical change
• Bacteria digest animal waste and produce biogas is chemical change.

  The biogas is then burnt as fuel are Chemical changes

• Both statements are physical changes

A piece of paper was cut into four pieces. What type of change occurred in the poperty of paper?

• Physical change
• Chemical change
• Both physical and chemical changes
• No answer

Balu stretched a rubber band. What does it represent?

• Physical change
• Chemical change
• Both physical and chemical changes
• No answer

Which metal is non-corrosive?

• Gold
• Iron
• Copper
• Magnesium

Burning of wood

• Reversible change
• Slow change
• Periodic change
• Chemical change

Digestion of food

• Reversible change
• Slow change
• Periodic change
• Chemical change

Formation of day and night

• Reversible change
• Slow change
• Periodic change
• Chemical change

Melting of ice

• Reversible change
• Slow change
• Periodic change
• Chemical change

Galvanisation

• Due to chemical change
• The process of depositing one metal on another metal
• Slow change
• Physical change