Question

1.what is melting point?(2m)
2.what is boiling point?(2m)
3.How water exists in three states of matter?(2m)
4.On hot sunny day why do people sprinkle water on roof are open ground?(2m)
5.Explain the effect of change of pressure?(2m)
6.What is the effect of change of temperature?(2m)
7.What is evaporation?(2m)

8.Explain giving for various factors and which the rate of evaporation depends(5m)
9.What is the fourth state of matter?(1m)​

Answer 1

1 the temperature at which a substance melts is called melting point

2 the temperature at which a substance boils is called boiling point

3 ice liquid vapour

4 so that cool breeze can come due to the evaporation of water

5 pressure increases then the heat changes due to which water changes its state

6 change in physical characteristics

7 evaporation is the process in which a substance loses water without reaching its boiling point

8 rate of evaporation depends on temperature

atmostpheric pressure wind

PLASMA(bec) is the 4 state of matter

Answer 2

1.melting point is 0°C

2.boiling point 100°C

3.solid-ice

liquid-water

gas-water vapour

4.As the roof is hot during the day at night the temperature downs but then to the roof is hot so, to make it cool we put water to it.

7.the change of state from water to vapour with the help of boiling is called evaporation.