Electrical Concepts and Wave Properties Explained
Electric Field
The electric field is the area of space around a load where electrical forces exert attraction or repulsion.
- The field strength depends on the load generator.
- The greater the load, the stronger the field.
- The further we move from the load generator, the weaker the field.
Capacitors
Capacitors store energy until required for use. They consist of two conductors, one positive and one negative, that support more capacity induction.
Ammeter
An ammeter measures the current in a circuit. It is placed in series so that the current through the ammeter and the bulb are the same.
Voltmeter
A voltmeter is used to measure the potential difference between two points. It must be placed between two points on either side. One of the terminals of the voltmeter is placed before the lamp and the other after.
Ohmic and Non-Ohmic Conductors
Ohmic conductors remain constant, while non-ohmic conductors do not remain constant, even if the voltage varies.
Vector and Scalar Quantities
A vector quantity includes the force of attraction or repulsion. A scalar quantity includes charge, electric potential, and electric power.
Electrification by Induction
Electrification by induction does not require direct contact between an electrical body and another neutral body to electrify the second. Just bring the first body close to the second (Faraday cage).
Measurement Principles
Energy Conservation
Energy is neither created nor destroyed, only transformed from one form to another. In these transformations, energy remains constant. In the case of mechanical energy, this is true in the absence of friction and without the intervention of any external work; the sum of kinetic and potential energy remains constant.
Isolated Shock
In an isolated shock, there is no energy exchange with the environment. Total momentum is conserved.
Elastic Shock
In an elastic shock, there is energy transfer. Kinetic energy is conserved, meaning it is not lost due to deformation of the bodies. Momentum is also conserved.
Plastic Shock
In a plastic shock, bodies remain attached. Deformation is at a maximum. Energy is not conserved.
Inertia
If no net force is exerted on a body, then the body either remains at rest or moves in uniform rectilinear motion.
Mass
When a net force acts on a body, acceleration occurs, and both quantities are directly proportional. The constant of proportionality is the mass of the body.
Action and Reaction
When a body A exerts a certain force (action) on another body B, body B also exerts a force of equal magnitude and opposite direction (reaction) on body A.
Waves
A wave is a perturbation that propagates in space and is characterized by the transport of energy but not matter.
- Crest: Maximum point of a wave.
- Valley: Minimum point of a wave.
- Size: Xv
- Period: The time between the emission of two consecutive waves.
- Frequency: The number of waves emitted every second.
- Wavelength: The distance between peaks or valleys.
- Node: Zero function.
Types of Waves
- Transverse Waves: Particles vibrate perpendicular to the direction of propagation (e.g., radio waves). Transverse waves can be mechanical or electromagnetic.
- Longitudinal Waves: Particles vibrate in the same direction as the propagation (e.g., sound). Mechanical waves are always longitudinal.
- Mechanical Waves: Need a material medium for propagation (e.g., sound waves).
- Electromagnetic Waves: Do not require a material medium for propagation (e.g., light).
Wave Phenomena
- Reflection: The change in direction of a wave that occurs at the boundary between two media, such that the wave returns to the initial medium (e.g., reflection of light, sound, and water waves).
- Refraction: The change of direction experienced by a wave passing from one medium to another.
- Diffraction: A wave going around an obstacle (e.g., you can hear a person who is in another room with the door open or through a window with an opening).
Sound Properties
- Intensity: Allows differentiation between strong and weak sounds.
- Tone and Frequency: Distinguishes high-pitched (treble) sounds from low-pitched (bass) sounds. High frequency corresponds to high-pitched sounds, and low frequency corresponds to low-pitched sounds.
- Timbre: Allows distinguishing sounds of equal intensity (frequency) and tone (amplitude) produced by two different sound sources.
Doppler Effect
The Doppler effect refers to the frequency shift that waves undergo when the source of the waves and/or the observer are moving relative to the medium. The frequency increases when the source and receiver approach and decreases when they move away.
Sound Propagation
Sound does not propagate in a vacuum because sound, being a mechanical wave, needs a medium for propagation, whether solid, liquid, or gas. In a vacuum, there is no such medium.