Page 146 - WCS - Electrical

WORKSHOP CALCULATION & SCIENCE - CITS

- Convection currents are responsible for various natural phenomena like wind, ocean currents, and atmospheric
circulation.
Radiation
- Radiation is the transfer of heat through electromagnetic waves. It does not require a medium and can occur
through a vacuum.
- All objects emit radiation, with the rate of emission depending on the object’s temperature and surface
properties.

Thermal Expansion
- Thermal expansion refers to the increase in size (volume, length, or area) of a substance in response to an
increase in temperature.

- The coefficient of thermal expansion quantifies how much a material expands for a given temperature change.
- The formula for linear expansion is ΔL = αLΔT, where ΔL is the change in length, α is the coefficient of linear
expansion, L is the original length, and ΔT is the change in temperature.
These concepts are fundamental in understanding the behavior of matter in response to heat and temperature
changes, as well as the mechanisms of heat transfer.
Specific Heat Capacity
- Specific heat capacity is the amount of heat required to raise the temperature of a unit mass of a substance
by one degree Celsius.
- It varies between different substances and reflects their ability to store or release heat.
- Water has a high specific heat capacity, making it useful for moderating temperature changes in the environment.

Thermal Capacity
- Thermal capacity is the heat energy required to raise the temperature of an object by a certain amount.
- It is directly proportional to the object’s mass and its specific heat capacity
Latent Heat
- Latent heat is the heat absorbed or released during a phase change (e.g., melting, vaporization) at a constant
temperature.
- It does not result in a temperature change but affects the substance’s state.
Water Equivalent

- Water equivalent is the mass of water that would absorb or release the same amount of heat as a given object
when its temperature changes by a certain amount.
Mechanical Equivalent of Heat

- The mechanical equivalent of heat is the amount of mechanical work equivalent to a given amount of heat
energy. It relates the units of mechanical energy (e.g., joules) to units of heat energy.
Different Temperature Measuring scales and there relation.
Temperature Scales

Temperatures are calibrated between two fixed reference points namely the freezing point of water, and the
boiling point of water.
i. Fahrenheit Scale: In British System unit of temperature is degree Fahrenheit. In this system at normal
atmospheric pressure the freezing point of water is 32° and boiling point of water is 212° . The Range between
32° and 212° is 180 which is divided into equal parts and one part is called 1°F.
ii. Centigrade Scale: In metric system the unit of temperature is degree centigrade. In this case the freezing
point of water is 0° at normal atmospheric pressure and boiling point is 100° The difference between 0° and
100° is divided into 100 equal parts and one part is called 1° C.

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CITS : WCS - Electrical - Exercise 12