Question

true or false
When water is heated, it changes intoice. ( )

5. Air is an opaque material. ( )

6. A policeman, controlling the traffic wears a mask to prevent the dust particles from

entering his respiratory system through breathing. ( )

7. Drains get choked due to plastics thrown by us. ( )​

Answer 1

1) False

2)False

3)True

4)True

Answer 2

(a) The temperature of a substance remains unaffected during its change of state.

(b) Ice melts at 100°C.

(c) Water at 100°c has more heat than the steam by 100°C

(d) Evaporation of a liquid causes cooling.

(e) Water evaporates only at 100°C.

(f) Boiling takes place at all temperature.

(g) Evaporation takes place over the entire mass of the liquid.

(h) The process of a gas converting directly into solid is called vaporization.

(i) At high altitude water boils above 100°C.

(j) The melting point of ice is 0°C.