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" »

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

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" »

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

Viscous friction forces cause the fluid layers in direct contact with a solid surface to adhere to it, resulting in no relative motion. Additionally, there cannot be any relative motion between the fluid and the wall perpendicular to the surface. Therefore, the boundary condition for a solid wall is:

(Wall-fluid relative velocity). For an ideal fluid without frictional forces, the condition is:

The force acting on a solid wall can be expressed as:

The force per unit area is then:

This represents the normal force to the surface (outgoing and incoming fluid at the solid). The first term represents static pressure, and the second term represents the viscous friction force acting on the surface. For a surface separating two immiscible fluids, the... Continue reading "Fluid Mechanics: Boundary Conditions and Dimensional Analysis" »

How is Sound Produced? Through Vibration and Resonance

Vibrations: Sound is produced as a result of the vibration of a medium or object. Sound always occurs because of a vibration.

Resonance: Frequencies are called natural or characteristic frequencies of vibration that are exhibited when they are left swinging or vibrating. Resonance occurs when the system is forced periodically with a frequency (rhythm) that coincides with some of its natural frequencies. This increases energy.

Vibrational Motion: The motion made by a body occupying symmetrical positions successively to a position of equilibrium.

Fundamental Concepts of Motion

• Vibration: The path of a moving body in vibration from passing through a point in its path until it returns to the same

Motion in Physics

Introduction to Motion

Kinematics is the branch of physics that studies movement. Objects can be in two states: at rest or in motion. An object is in motion when it changes its position over time relative to a fixed reference point. A reference system is something assumed to be at rest, against which movements are described. It's crucial to use a reference system when studying the motion of an object.

Understanding Rest

A body is at rest when its position doesn't change over time relative to other objects we consider stationary. To study movement, we need to know:

• Position: The body's location in space relative to a reference system.
• Trajectory: The line describing the body's movement (straight or curved).
• Distance: The length covered

Henry's Experiment

If a driver or wire moves perpendicular to a magnetic field, it causes a potential difference across the ends of the conductor. This potential difference causes a current if the driver is part of a closed circuit.

Faraday's Law

Any change in magnetic flux through a circuit causes an induced current. This is produced by a known electromotive force (induced EMF), which exists only for the duration of this change in flux and is proportional to the rate of change of flow.

Lenz's Law

The direction of the induced current is such that it opposes the cause that produces it.

Alternator

An alternator consists of a flat coil of N turns, rotating with constant angular velocity within a uniform magnetic field B. In the coil, an EMF is induced... Continue reading "Electromagnetism and Optics: Principles and Applications" »