Notes, summaries, assignments, exams, and problems for Physics

Understanding Light: Key Optical Concepts

Index of Refraction

We define the index of refraction (n) of a medium as the ratio between the speed of light in a vacuum (c) and the speed of light in that medium (v):

n = c / v

Laws of Reflection of Light

When light rays strike a surface, they undergo a rebound that follows these laws:

1. The incident ray, the normal to the surface, and the reflected ray all lie in the same plane.
2. The angle of incidence (i) is equal to the angle of reflection (r), and they are on opposite sides of the normal: i = r.

Laws of Refraction of Light

When light passes from one transparent medium to another where the speed of light changes, its direction also changes. This phenomenon is known as the refraction of light, governed by these... Continue reading "Fundamentals of Light: Reflection, Refraction, and Lenses" »

Definitions AC. The changing of direction.
CURRENT. The meaning does not change, but may change in value. CURRENT PERIODIC. That which is repeated in cycles with the same period. PERIOD. Time it takes one cycle. CYCLE. Set starting values such that at any one walking back to the all the values of the signal. FREQUENCY. Number of cycles a second. The unit hertz. Resonance frequency is that frequency that makes a circuit is resistive (the circuit contains inductors and capacitors). Or half-power frequency cut-off frequency filter. That often happens in these situations simultaneously: the power half the maximum, the load voltage is 70% of the maximum, the phase angle is 45 degrees. BANDWIDTH. Difference between the cutoff frequencies. OR QUALITY

... Continue reading "Essential AC Circuit Terminology and Definitions" »

Fundamental Concepts in Fluid Mechanics

Pressure and Phase Changes

• Evaporation: The constant movement of molecules on the surface of a liquid, allowing them to escape into the atmosphere.
• Boiling: Occurs when the pressure to which a liquid is subjected equals its vapor pressure.
• Vapor Pressure: The partial pressure exerted by molecules in the gaseous state within a container when occupying a space above a liquid.
• Saturation Pressure: The state where there is a dynamic balance between the number of molecules that evaporate and condense.
• Cavitation: A phenomenon where, if the local pressure (p) in a liquid drops to or below its vapor pressure, the liquid rapidly evaporates, forming vapor bubbles. These bubbles then move and collapse violently within

... Continue reading "Fluid Mechanics Essentials: Pressure, Viscosity, and Hydrostatic Principles" »

Earth's Gravitational Field

The gravitational field of the Earth is the disturbance that occurs in the space surrounding a body having mass. The intensity of the gravitational field at a point in space is the force with which the Earth attracts a unit mass located at that point. The weight of a body is the force with which the Earth attracts it. The gravitational potential energy of a mass m at a point in Earth's gravitational field is the work performed by the gravitational field to move the mass m from that point to infinity. The gravitational potential at a point in Earth's gravitational field is the work performed by the gravitational field to move the unit mass from that point to infinity.

• Period of revolution: Time it takes a satellite

... Continue reading "Earth's Gravitational Field and Kepler's Laws of Planetary Motion" »

Fundamental Concepts in Geodesy and Measurement

The following definitions cover essential terminology related to Earth's geometry, measurement techniques, and coordinate systems.

Magnetic Poles

Defined as the points on the surface of the Earth where the magnetic field lines are perpendicular to the surface.

Geographic Poles

Defined as the points on the Earth's surface that intersect with the planet's axis of rotation.

Bounded System (Orthogonal Cylindrical Projection)

A system of orthogonal cylindrical projection is the most appropriate for the representation of land and figures whose vertical dimensions are much smaller than their horizontal dimensions. The height of a point ($q$) is measured relative to a reference plane and can be positive (... Continue reading "Essential Definitions in Geodesy and Land Surveying" »

Center of Buoyancy

The center of buoyancy is the center of gravity of the volume of water displaced by a float for a given condition. Also known as the center of thrust, as it is, for the purpose of stability, which regards the force applied. It is represented by the letter C and in some publications with the letter B to equate the "Center of Buoyancy" of English.

Since the ship moves in waves, the position of the center of buoyancy is variable and depends on the hull shape and volume submerged at that time. The curve in the transverse plane that describes the center of buoyancy for different angles of rocking is called the curve, and its center of buoyancy ray radii.

Transverse Metacentric

Since by definition the metacenter is in the vertical... Continue reading "Understanding Ship Stability and Maritime Forces" »

Sound Perception: The Subjective Factor

Sound perception is the subjective factor that involves physiological and psychological processes occurring in the ear and brain. It allows us to classify sounds as weak, strong, pleasant, or unpleasant. This perception depends not only on the sound's intensity but also on its frequency.

Sound Reflection

Sound reflection is a phenomenon where sound waves bounce off a surface and propagate in a different direction. This principle is utilized in various applications, such as in satellite dishes to focus signals.

Echo

An echo is a distinct phenomenon caused by the reflection of sound. We can distinguish an echo from the original sound if the reflected sound arrives with a time difference of at least 0.1 seconds.... Continue reading "Understanding Sound Phenomena: Perception, Reflection, and Waves" »

Concepts and Electromagnetic Phenomena

Magnetic Field Definition

Magnetic Field: The area which shows the effects of magnetic poles is said to have a magnetic field. A magnetic field is represented by lines of force.

Magnetism: Lines of force of a magnetic field created by a permanent magnet.

Magnets

• Magnets attract or repel each other, similar to electric charges.

Magnetic Magnitudes

Magnetic Flux Density (B): The number of magnetic field lines that cross the unit area (m²).

• Magnetic Flux (Φ)
• Magnetic Field Strength (H)

Electromagnetism

Electromagnetism involves the creation of a magnetic field through an electric current, or the creation of an electrical current in the presence of a magnetic field.

Biot-Savart Law

An electrical charge (q), which moves... Continue reading "Fundamental Concepts of Magnetism and Electromagnetism" »

1. What is an Electrical Accident?

An electrical accident is a process in which a person receives electrical energy, either directly or indirectly. This can range from simple electromagnetic radiation to situations where the victim becomes electrically coupled to the network.

2. Definition of Electrical Contact

Electrical contact refers to the probability of a human body being subjected to a potential difference, resulting in an electric shock due to the passage of current through it.

3. Physiological Effects of Electrical Current Above 5A

When an electrical current exceeding 5A passes through the human body, the following physiological phenomena may occur:

• Less than one cardiac cycle: Ventricular fibrillation, early electrocution (depending on the

... Continue reading "Electrical Accidents: Understanding the Risks and Safety" »

Plot Summary: Adrian Mole's Teenage Life

Adrian Mole lives with his parents and a dog, struggling with severe acne (spots). Initially, they appear to be a normal family, but problems soon arise. Adrian's attitude towards life is often highly dramatic.

A major source of drama involves his love interest, Pandora. Adrian is deeply in love with her, but his friend Nigel starts dating her first. Meanwhile, Adrian's mother, Pauline, has an affair with their neighbor, Mr. Lucas. Adrian's parents eventually divorce, and Pauline moves to Sheffield with Mr. Lucas. Adrian stays with his father.

Adrian regularly visits Bert Baxter, an elderly man he cares for. Bert later moves to an old people's home, where he meets Queenie. Adrian eventually manages to date... Continue reading "The Secret Diary of Adrian Mole: Plot Summary and Character Analysis" »