Essential Physics Principles: Electromagnetism & Thermodynamics

Fleming's Left-Hand Rule

This rule determines the direction of the force on a conductor when placed in a magnetic field. It is often used in the context of electric motors.

• If the index finger points in the direction of the magnetic field,
• And the middle finger points in the direction of the current,
• Then the direction of the thumb indicates the direction of the force on the conductor.

Fleming's Right-Hand Rule

This rule is used to identify the direction of induced current when a conductor moves within a magnetic field. It is fundamental to understanding electric generators.

• The thumb indicates the direction of the motion of the conductor.
• The index finger indicates the direction of the magnetic field.
• The middle finger indicates the direction of the induced current.

Right-Hand Thumb Rule (Ampere's Rule)

This rule helps determine the direction of the magnetic field produced by current flowing through an electrical conductor.

Imagine holding the conductor in your right hand:

• Your thumb points in the direction of the current.
• Then, your fingers curling around the conductor indicate the direction of the magnetic field lines of force.

Temperature-Time Graph: Water Phase Changes

This graph illustrates the temperature-time relationship as ice transforms into water and steam. Key observations include:

1. AB shows that, at a constant temperature of 0°C, ice changes to water.
2. The temperature at which ice changes to water is called the melting point of ice, which is 0°C.
3. Water at 0°C then begins heating, and its temperature gradually increases to 100°C.
4. BC shows an increase in temperature from 0°C to 100°C without a change in state (water remains liquid).
5. CD shows that, at a constant temperature of 100°C, water changes to vapor.
6. The temperature at which water changes to vapor is called the boiling point of water, which is 100°C.

Key Concepts of Latent Heat

Latent heat refers to the heat energy absorbed or released during a phase change at a constant temperature. Here are key definitions:

Specific Latent Heat of Vaporization

The amount of heat energy absorbed at a constant temperature by unit mass of a liquid to convert into its gaseous phase is called the specific latent heat of vaporization.

Latent Heat of Vaporization

The heat energy absorbed at a constant temperature during the transformation of a liquid into a gas is called latent heat of vaporization.

Latent Heat of Fusion

The heat energy absorbed at a constant temperature during the transformation of a solid into a liquid is called latent heat of fusion.

Specific Latent Heat of Fusion

The amount of heat energy absorbed at a constant temperature by unit mass of a solid to convert into its liquid phase is called the specific latent heat of fusion.