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

Laws of reflection and refraction
When a wave strikes the surface between two media of different refractive index, part of the wave is reflected and partly refracted (transmitted by other means). The laws of reflection and refraction tells us that:
· · Rays incident, refracted and reflected are on the same plane, called plane of incidence, which is perpendicular to the surface.
· • The angle of incidence, Oi, and the angle of reflection, Orson equal.
· • The angle of incidence and transmission / refraction angle, Ot are related by Snell's law: n1senOi = n2senOt, where n ₁ and n ₂ are the indexes on the first and second means.

Snell's law implies that if light passes half of higher index, the rays are close to normal (away from... Continue reading "Laws of Reflection, Refraction, and Light's Dual Nature" »

Fundamentals of Light Propagation

• The light propagates in a straight line in transparent and homogeneous media.
• The speed of light is approximately 300,000 km/s.

Refractive Index

The absolute refractive index of a substance is the ratio between the speed of light in a vacuum and its speed through the substance, represented by the letter n.

Laws of Reflection

• When light reflects off a specular surface, the incident ray, the reflected ray, and the normal lie in the same plane (first law of reflection).
• The angle of reflection equals the angle of incidence (second law of reflection).
• Images formed in flat mirrors are virtual, upright, and the same size as the object.

Spherical Mirrors

A spherical mirror is a portion of a sphere:

• When the inside of the cap

Electrostatic:
He studied electrical phenomena caused by static charge distributions, ie the electrostatic field of a charged body.

Gauss's law
Gauss's law says that the net electric flux c, through any Gaussian surface is equal to the net charge enclosed within the surface divided by "0:
Using Gauss's law, one can calculate the electric field due to several symmetric charge distributions.
Typical electric fields calculated using Gauss's law
Insulating sphere of radius R, uniform density and total charge Q
With r> R
With r <R
Thin spherical shell of radius R and total charge Q
With r> R
With r <R
Load lines of infinite length and charge per unit length
Outside the load line
Nonconducting infinite plane loaded with load... Continue reading "Fundamentals of Electrostatics: Laws and Fields" »

1. Heat: Heat is the energy created by the movement of atoms and molecules (groups of atoms). For example, thermal energy can be converted into heat. To increase a body's heat, its molecules must increase their speed. 2. Temperature: Temperature is a measure of the heat or thermal energy of the particles in a substance. It expresses the level of a body's heat. Thermal agitation is seen in the vibration of atoms or molecules of a body due to the amount of internal energy or heat it possesses. 3. Effects of Heat:

• Temperature Changes: When a body absorbs heat, its temperature increases.
• Resizing: When a body is heated, its heat energy increases, causing the body to expand and increase in volume.
• State Change: Heat can cause a body to change its state

Understanding the Microscope

The microscope is an optical instrument used to enlarge images.

Microscope Systems

• Mechanical System: Comprises the structural components that support the instrument.
• Optical System: A set of lenses arranged to magnify images.
• Lighting System: Parts that reflect, transmit, and regulate the light needed for observation.

Mechanical Components

The mechanical parts of the microscope include: the base (foot), the body tube, the arm (handle), the stage (plate), the stage clips, and the coarse and fine adjustment knobs.

Optical and Lighting Functions

• Optical System: Responsible for reproducing and enhancing images through a set of lenses.
• Lighting System: Directs sunlight or artificial light toward the object being observed.
• Light

Free Surface Flows

Free surface flows occur when a liquid circulates without filling the tube that carries it, or when water is driven by a canal. In these cases, the liquid is at atmospheric pressure. We say that the pipe is working as a channel flow. This is also referred to as sewer flow, flow without pressure, gravity flow, or free flow.

Surface Current Force and Pressure Flow

When the liquid completely fills a conduit of circular cross-section and exerts pressure on the walls of the pipe, it is said to be working as a conduit under pressure. This is known as pipe flow by pressure or forced flow. In this case, the movement of the fluid is due to the pressure present inside the duct.

Fluid Flow Regimes

Laminar Flow

In laminar flow, each element... Continue reading "Fluid Dynamics: Free Surface and Pressure Flow Principles" »

Force

A cause that can produce changes in the motion or shape of an object.

Action-at-a-Distance Forces

Forces whose effects are observed without the bodies needing to be in physical contact with each other.

Hooke's Law

The deformation of an elastic body is directly proportional to the force that produces it.

Scalar Quantities

Quantities defined by a number and a unit.

Vector Quantities

Magnitudes defined by a magnitude, direction, sense, and point of application. They are represented by a vector, which is an oriented segment in space.

Net Force

The single, resultant force equivalent to all forces acting on a particular body.

Equilibrium Conditions

A body is in equilibrium if the resultant of the forces acting on it is zero.

Static Equilibrium

A situation... Continue reading "Fundamental Principles of Force, Motion, and Dynamics" »

Electric Charge

Electric charge exists in two types: negative (like the electron) and positive (like the proton). It is measured in coulombs (C).

Coulomb's Law

Charges repel if they have the same sign, or attract if they have opposite signs. The force increases with the product of the charges and decreases proportionally to the square of the distance separating them.

Electric Field

A vector field where the direction is defined by the path a positive charge would follow. Its modulus is the ratio of the electric force to the value of the test charge.

Superposition Principle

The vector sum of individual forces and fields acting on any charge in the proximity of others.

Field Lines

The path followed by a positive charge located in a field. These open lines... Continue reading "Fundamentals of Electric Charge, Fields, and Energy" »

Forces Between Flows of Ampere Straight and Parallel: Definition

A conductor carrying an electric current creates a point around a magnetic field, which is directly proportional to the intensity of the current through the conductor I, and inversely proportional to the distance d from the conductor to the point under consideration.

If you place a conductor carrying a current in a magnetic field, the field exerts an interaction on it that depends upon the value of field strength B, the current I flowing through the conductor, and the length of the conductor l. The direction of F is perpendicular to the plane determined by the vectors B and l. The meaning of the interaction is fixed by the right-hand rule.

When two conductors carrying electric currents... Continue reading "Understanding Magnetic Forces Between Parallel Conductors" »

Balance

A body is in equilibrium when at rest or when moving with uniform rectilinear motion. Some conditions are:

• When a body acts on a single force, it cannot be in balance.
• Two equal and opposite forces acting on a body produce equilibrium.
• The total strength of various forces must be zero for a body to be in balance.

Resultant Force

The resultant force (R) is the force that substitutes various forces, and its effect is the same as all the initial forces together. The calculation of the force resulting from a group of them acting on a body is called the composition of forces.

Resultant Force of Forces Applied in the Same Direction and Sense

• The point of application, direction, and sense will be the same as those of the component forces.
• The module