Heat ( All Question based on NCERT )

 

1. Heat is a physical quantity. Whose unit is joule or calorie. The value of one calorie is 4.18 joules.

2. Thermal expansion is lowest in solids and highest in gases.

3. The volume of water decreases between zero (0) degrees Celsius and 4 degrees Celsius, while it increases above four degrees Celsius.

4. The density of water is maximum at 4 degrees Celsius.

5. The first law of thermodynamics is also called the law of conservation of energy while the second law is also called the law of zero.

6. Due to the high specific heat of water, the climate of the places near the sea remains temperate.

7. Due to the high specific heat of water, water is filled in the engine radiator to cool it.

8. It is due to latent heat that the mountains become cold not at the time of snow falling but later.

9. The boiling point of pain decreases when the pressure decreases whereas the boiling point increases when the pressure is increased.

10. When a soluble substance is found in a liquid, its demand is mostly reduced.

11. The presence of water in the air is the root cause of humidity.

12. Salt gets sweaty if kept open during the rainy season because there is more humidity in the air during the rainy season.

13. Water droplets collect outside a glass filled with ice. The reason for this is that the air vapor that comes in contact with the surface of the glass gets condensed and freezes on the surface of the glass.

14. To prevent the snow from melting, the snow is kept wrapped in sackcloth, because sackcloth is a poor conductor of heat.

15. Under the influence of heat, the shape of the substance expands in volume or volume.

16. Sand absorbs heat during the day and emits heat at night, hence sandy places are very hot during the day and very cold at night.