Heat

Figure below shows the change of the temperature when a gas is cooled to become solid. Q & A Q: Why the temperature remained unchanged from Q-R and S-T? A: The temperature remains unchanged because the heat released during the formation of the intermolecular forces compensates the heat losses to the surrounding. Q & A … Read more

Figure below shows the change of the temperature when a solid is heated until it become gas. Note:B to C Temperature remain unchanged because the heat absorbed is used to overcome the force between the particles in the solid. The heat absorbed to change a solid to liquid is called the latent heat of fusion. … Read more

Latent Heat The latent heat is the heat absorbed or given out at constant temperature during the change of state of matter. When a solid melt, heat is absorbed but the temperature remains constant. When a liquid is boiling, heat is also absorbed but the temperature again remains constant. The heat absorbed or given out … Read more

Sea Breeze The land has a lower heat capacity than seawater. Therefore, in the day time, the temperature of the land increases faster than the sea.  Hot air (lower density) above the land rises. Cooler air from the sea flows towards land and hence produces sea breeze. Land Breeze The land has a lower heat … Read more

Cooking Pot Different parts of a cooking pot are made up of different material. The base of a cooking pot is usually made up of copper because copper has low specific heat capacity so that it needs less heat to raise up the temperature. copper is a good heat conductor. copper has high density. The … Read more

Conversion of Gravitational Energy to Thermal Energy mgh=mcΔθ Example 1:The Angel Falls in Venezuela is 979 m in height. Calculate the rise in temperature of the water when the waterfall from the top to the bottom. (Assume that all the potential energy loss of the water is converted to heat) [The specific heat capacity of … Read more

When 2 objects/substances are in thermal contact, there will be a net flow of thermal energy from the object/substance with a higher temperature to the object/substance with lower temperature. If we assume there is no thermal energy loss to the surrounding Thermal energy loss = Thermal energy gain Example 1: A 0.5 kg block of … Read more

Example 1:How much heat energy is required to change 2 kg of ice at 0°C into water at 20°C? [Specific latent heat of fusion of water = 334 000 J/kg; specific heat capacity of water = 4200 J/(kg K).] Answer:m = 2kgSpecific latent heat of fusion of water, L = 334 000 J/kgspecific heat capacity … Read more

Specific Heat Capacity Specific heat capacity is defined as the amount of heat required to change the temperature of 1 kg of a substance by 1°C. Specific heat capacity is a physical quantity used to compare the heat capacity of a given material of the same mass. It is the measure of how much energy … Read more

Heat Capacity Heat capacity is the measure of the ability of an object to store heat as its temperature changes. It is the measure of the amount of heat required to change the temperature of an object by 1°C. The SI unit of heat capacity is joules per Kelvin (J/K). The heat capacity of an … Read more