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

Light Dispersion Explained

Dispersion is the separation of incident light as it passes through a physical medium into elementary components characterized by their specific wavelengths. The only medium that is completely non-dispersive is a vacuum. The easiest way to observe the dispersion of light is through a prism. When a beam of white light, such as sunlight, passes through a prism, it experiences deviation and dispersion. The incident light is separated into elementary colors because they do not propagate through the prism at the same speed and emerge at different angles of refraction. The resulting spectrum of rainbow colors, ordered from higher to lower wavelengths, is known as the white light spectrum.

Geometrical Optics

Light propagation... Continue reading "Understanding Light Dispersion and Geometrical Optics Principles" »

Reflection of Light and Its Fundamental Laws

The reflection of light is the change of direction a light beam undergoes when striking the surface of bodies.

Types of Reflection

• Specular reflection: This occurs when light reflects off a polished surface, such as a mirror.
• Diffuse reflection: This occurs when the surface is rough and the light is reflected in all directions.

The Two Fundamental Laws of Reflection

The reflection of light on a flat surface follows two fundamental laws:

1. The incident ray, the normal, and the reflected ray are all on the same plane.
2. The angle of incidence equals the angle of reflection.

Electromagnetic Waves and the Nature of Color

Different electromagnetic waves that we perceive as red, yellow, green, blue, indigo, and violet... Continue reading "Principles of Light Reflection and Human Vision" »

Irradiance

This is the power emitted by the body per unit area and wavelength (W · nm^-1 • cm^-2). Furthermore, the irradiance of a lamp that is showing is similar to a black body.

Emissivity

It is the ratio of the irradiance of the lamp and a black body at the same temperature:

Emissivity (e, t) = I (lamp) (E, T) / I (black body) (E, T).

Gray Body

This occurs when the emissivity is independent of the wavelength of the lamp in question.

Deuterium Lamp

It is a low-pressure lamp that has a smooth continuum between 200 and 400 nm, and from this last value, the spectrum is more irregular with a large number of peaks. It also has a life of a few hundred hours. The QTH lamp (quartz-tungsten-halogen) issues more visible light than the Deuterium lamp in the... Continue reading "Spectrophotometry Basics" »

Rotary Paddle Fixed-Point Detectors

A rotary engine turns paddles through a spring. This rotation is continuous as long as the material does not come into contact with the blades. If these shovels stop but the engine keeps turning, the spring expands until it hits a limit switch that stops the engine and provides an external electrical contact. When the level is low, the spring returns to its position, the motor starts again, and the switch output changes its position. The pallet can be flexible or rigid to adapt to different working conditions.

Electromechanical Continuous Level Meters

This system uses a small mobile weight supported by a cable from the top of the silo via pulleys. A programmer and motor set a duty cycle for the weight. This... Continue reading "Industrial Solid Level Measurement Technologies" »

Darwinism and Natural Selection

Darwinism describes the struggle for survival caused by limited resources, resulting in a process of natural selection. The fittest individuals—those with the best characteristics to adapt to their environment—survive, while the least adapted perish. These survivors transmit their advantageous traits to their offspring.

Origin of the Cosmos: The Big Bang

The Big Bang was an initial expansion of the universe from all points of a field. This event did not occur in one specific location; rather, it was an amorphous state subjected to extreme temperatures that expanded simultaneously in all directions. As the universe expanded, space filled with light and matter, causing celestial bodies to separate.

Future Scenarios

Kinematics Formulas and Motion Equations

Vector Description of Motion

Rectilinear Motion

Circular Motion

Optical and Thermal Properties

1. Optical Properties

The human eye is sensitive to wavelengths ranging from approximately 400 nm (violet) to 700 nm (deep red). For an object to be visible, it must either emit light or reflect light incident from an external source.

In teeth, polychromatic light is a mixture of several wavelengths. Consequently, the perceived color of an object can vary significantly under different light sources; this phenomenon is known as metamerism. Therefore, color selection must be performed under two or more different light sources, one of which should be daylight.

Fluorescence is the ability of certain objects to change the wavelength of incident light, transforming invisible radiation into visible light, which provides... Continue reading "Optical, Thermal, and Biocompatibility Properties of Dental Materials" »

Sentence Types and Structures

Coordinated Sentences

There are two propositions; both are simple propositions. They possess syntactic autonomy and are joined by a non-coordinating link. If a sentence has these characteristics, it is a coordinated sentence.

• Copulative: y, e
• Disjunctive: o, u
• Adversative:
  • Partial: but, again, yet, nevertheless
  • Total: but, rather
• Distributive: well... well, now... now, ya... ya, some... others...
• Explanatory: that is, indeed, for example...

Subordinate Sentences

There are two propositions, one of which (the first) can have autonomy, but the subject cannot. When taken out of context, the second proposition lacks syntactic autonomy because it depends on the verb of the first proposition. The second proposition is joined to... Continue reading "Advanced Sentence Structures and Linguistic Analysis" »

Fundamental Concepts of Electricity

Electricity: is defined as electron flow through a conductor.

Classification of Materials

• Conductors: These are materials that have a great facility for electricity to pass through them.
• Semiconductors: These are intermediate materials in the ability to conduct electrons at higher temperatures.
• Insulators: These are materials that do not conduct electrons through them and can allow charge accumulation.

Electrical Charges and States

• Positive: When a material is rubbed against another, it loses electrons and tries to attract others.
• Negative: When a material is rubbed with another, it gains electrons and repels another body.
• Neutral: When a material is rubbed with another and does not win or lose electrons.

Detection