Fundamental Physics Definitions: Pressure, Heat, Fields

Pressure Definition

Pressure: Indicates the relationship between an applied force and the area over which it acts. Reducing the area over which a force acts increases the pressure.

Hydrostatic Pressure

Hydrostatic pressure: It is the pressure exerted by a liquid at rest on the bottom and sides of its container due to gravity.

Atmospheric Pressure

Atmospheric Pressure: The pressure exerted by the Earth's atmosphere on all bodies within it.

Pascal's Principle

Pascal's Principle: Any pressure exerted on a confined fluid is transmitted undiminished to every portion of the fluid and the walls of its container.

Archimedes Principle

Archimedes Principle: Any body immersed in a fluid (liquid or gas) experiences an upward buoyant force equal in magnitude to the weight of the fluid it displaces.

Volume Flow Rate (Expenditure)

Expenditure (Volume Flow Rate): The volume of fluid flowing through a conduit per unit of time.

Mass Flow Rate

Flow (Mass Flow Rate): The mass of fluid that flows through a pipe per unit of time (e.g., per second).

Bernoulli's Theorem

Bernoulli's Theorem: For an ideal fluid (inviscid and incompressible) in steady flow, the sum of its kinetic energy per unit volume, potential energy per unit volume, and pressure remains constant along a streamline.

Heat Propagation Methods

Forms of Heat Propagation:

1. Conduction: Heat transfer due to collisions between adjacent molecules within a substance, primarily occurring in solids.
2. Convection: Heat transfer caused by the bulk movement of a heated fluid (liquid or gas).
3. Radiation: Heat transfer through electromagnetic waves, which can travel through a vacuum at approximately 300,000 km/s (the speed of light).

Linear Thermal Expansion

Linear Expansion: The increase in length experienced by a solid body (like a wire) when its temperature is increased.

Superficial (Area) Thermal Expansion

Superficial (Area) Expansion: The increase in the surface area of a body when it is heated.

Volume Thermal Expansion

Volume Expansion: The increase in the overall volume (considering length, width, and height) of a substance when heated.

Coulomb's Law

Coulomb's Law: The electric force of attraction or repulsion between two stationary point charges (q1 and q2) is directly proportional to the product of the magnitudes of the charges and inversely proportional to the square of the distance (r) between them.

Electric Field Concept

Electric Field: An invisible field surrounding an electric charge that exerts a force on other charges placed within it. Its presence and intensity can be detected and measured by its effect on test charges.

Electric Potential Definition

Electric Potential: A scalar quantity representing the electric potential energy per unit charge at a specific point in an electric field.

Magnetic Field Concept

Magnetic Field: The region surrounding a magnet or a moving electric charge within which the force of magnetism acts and its influence can be detected.

Intensive Properties

Intensive properties are those that do not depend on the amount of substance or the size of the system. They are not additive. Examples include temperature, pressure, density, velocity, and specific volume (volume per unit mass). An intensive property can be a scalar or a vector quantity.

Extensive Properties

Extensive properties are those that do depend on the amount of substance or the size of the system. They are additive. Examples include mass, volume, energy, and momentum.

Intensive vs. Extensive Relationship

If H denotes an extensive property and h denotes the corresponding specific intensive property (per unit mass), the relationship can often be expressed as: h = H / m (where m is the mass). This defines the intensive property as the amount of the extensive property per unit mass.