Light and Sound Practice Flashcards

100 flashcards covering waves, sound, light properties, communication, navigation, medicine, and innovation based on lecture notes.

What is the definition of a wave according to the notes?

A disturbance that transfers one energy to another passing through time

What is a mechanical wave?

A type of wave that requires a material medium (may be solid, liquid, or gas)

What is sound defined as in the transcript?

A mechanical and longitudinal wave produced by vibration

Through what does sound travel?

Particles in a medium

What tools can be used to detect sound?

Ears or microphones

List three examples of sound sources mentioned in the lecture.

Voice, speaker, and instruments

What are two common uses for sound mentioned in the notes?

Communication and music

What is an electromagnetic wave?

A wave that does not require a material medium and can travel through empty space/vacuum

List the types of waves in the electromagnetic spectrum provided.

Radio, Microwave, Visible Light, Infrared, Ultraviolet, x-ray, and Gamma

What are the characteristics of a radio wave compared to others?

Longer wavelength, lower frequency, and lower energy

What are the characteristics of a gamma ray compared to others?

Shorter wavelength, higher frequency, and higher energy

How can light be detected?

Using your eyes or light sensors

What are the four sources of light listed in the notes?

Sun, Lamp, LED, and Laser

How is light characterized as a wave?

Electromagnetic and transverse wave

What are two primary uses for light?

Lighting and imaging

Which type of wave is described as non-existent for light?

Compressed wave

What is the definition of a compressed wave?

Waves without space

What is the definition of a rarefaction wave?

Waves with space

For sound, what does a greater amplitude result in?

Greater sound intensity

For light, what does a greater amplitude result in?

Greater brightness

How is wavelength defined?

The distance between 2 corresponding points of consecutive waves, measured from one crest to another crest

What is amplitude?

The maximum displacement of a wave from its starting/resting position

What is the crest of a wave?

The highest point of a wave

What is the trough of a wave?

The lowest point of a wave

What is the definition of frequency?

The number of complete wave cycles passing a point every second

What is the unit used for frequency?

$$Hz$$

What is the relationship between wavelength and frequency?

They have an inverse relation

What is wave speed?

How fast the wave displacement travels

Between light and sound, which travels faster?

Light travels faster than sound

What is the approximate speed of light?

$$\approx 300,000,000\,m/s$$

What is the approximate speed of sound given in the notes?

$$343\,m/s$$

What is reflection?

When light strikes a surface and returns to the original medium; light bounces from a surface

How does surface texture affect reflection?

A smoother surface leads to a smoother reflection

What is the primary benefit of reflection for human vision?

It makes it possible to see objects

List six examples of objects that demonstrate reflection.

Mirror, calm water, vehicle side mirror, polished metal, reflective road signs, and periscope

What is refraction?

The bending of light as it passes from one transparent medium to another

What is the medical term for nearsightedness related to refraction?

Myopic

What is the medical term for farsightedness related to refraction?

Hyperopic

List five examples of items that use refraction.

Eyeglasses, magnifying lens, pencil in water, camera lens, and telescope

What is transmission?

Light passing through a material

Define a transparent material.

A material where most light can pass through with minimal thermal energy

Give an example of a transparent material.

Clean glass

Define a translucent material.

A material where some light can pass through but it scatters

Give an example of a translucent material.

Frosted glass

Define an opaque material.

A material where most visible light is blocked or absorbed

What determines the color seen on an opaque object?

The reflected visible light that can be seen by the naked eye

List four examples of opaque materials.

Wood, metal, cardboard, and thick walls

What is absorption?

When a material takes in light energy

How does thermal energy relate to white or light colors?

They have the least thermal energy

How does thermal energy relate to black or dark colors?

They have high thermal energy

What is dispersion?

The separation of white light into its component colors

What is a common example of dispersion?

White light passing through a prism or droplet that creates a rainbow

What is diffraction?

The spreading of waves around obstacles or through small openings

What is a specific example of diffraction mentioned in the notes?

CD color patterns

What is interference?

When 2 or more light waves overlap and may strengthen or weaken each other

List two examples of interference.

Bubbles and holographic materials

How does fiber-optic communication carry information?

Through pulses of light

What are the strands in fiber-optics made of?

Very thin strands of glass or plastic

How is light kept within a fiber-optic strand?

Through repeated internal reflection

List four uses for fiber-optic communication.

Internet connection, telephone networks, cable TV systems, and data centers

Name a medical use for fiber-optics.

Medical viewing instruments

What is the first benefit of fiber-optics mentioned in the navigation section?

Fast transmission of information

What is the second benefit of fiber-optics mentioned in the notes?

High data capacity

What is a benefit of fiber-optics regarding interference?

Reduced interference from ordinary electrical signals

What distance-related benefit do fiber-optics provide?

Ability to carry information over long distances

What is infrared radiation?

Light that is invisible to the human eye but can be detected by electrical sensors

What is abbreviated as IR?

Infrared communication

What is the definition of Infrared Communication technology?

A wireless technology that uses invisible (infrared) light to transmit data between devices

List three applications for infrared communication.

Remote controls, short-range communication, and motion sensors

How do visible light signals communicate information?

Through color, position, intensity, and flashing patterns

List three examples of visible light signals.

Traffic lights, vehicle lights, and emergency beacons

What is the purpose of lighthouses and maritime signals?

Provide navigational guidance, warn of coastal hazards, and mark safe harbor entrances

What are reflective markers?

Objects that return light back toward its source

List four examples of reflective markers.

Reflective road signs, lane markers, safety clothing, and vehicle reflections

What does LiDAR stand for?

Light Detection and Ranging

What is the first step in the LiDAR process?

Sends laser pulses towards an object/source

What is the second step in the LiDAR process?

Detects returning reflected light

What is the third step in the LiDAR process?

Uses travel time of the pulse to obtain distance information

What is a primary safety consideration regarding laser emitters?

Do not look directly into laser emitters

To maintain safety, where should laser emitters NOT be pointed?

At people, vehicles, or aircraft

What navigation rule should be followed for safety?

Follow traffic light and signal meanings

What vehicle maintenance is required for light safety?

Keep vehicle lights properly maintained

What type of light should be avoided to prevent distracting drivers?

Unnecessary bright lights

What is endoscopy?

An instrument used to review internal areas of the body where light illuminates internal structure and the image is transmitted to a viewing system

What three components are used in an endoscopy system?

Light source, lenses, and fiberoptics/electronic cables

What is pulse oximetry?

A technique using selected wavelengths of light sent through a finger/body part to estimate blood oxygen saturation and pulse rate

What is the normal range for oxygen level in pulse oximetry?

$$95-99\%$$

What does an oxygen level of less than $95\%$ suggest?

Low Hemoglobin

What is Hemoglobin?

An iron-rich protein in red blood cells that carries oxygen

What are medical lasers used for?

Certain eye and dental procedures

Who must operate medical lasers?

Trained professionals

What is phototherapy?

The use of selected wavelengths of light under professional supervision

List four examples of light in entertainment from the notes.

Projectors, photography, video recording, and cinema screens

List three additional examples of light in entertainment.

Stage lighting, laser shows, and digital displays

What does LED stand for?

Light Emitting Diodes

How does an LED produce light?

It emits light when electric current passes through it

What does the acronym LASER stand for?

Light Amplification by Stimulated Emission of Radiation

What is a laser device?

A device that makes a very narrow and strong beam of light through optical amplification based on the stimulated emission of electromagnetic radiation

How are holograms produced?

From a recorded light-interference pattern

List four specific applications for holograms mentioned in the innovations section.

Security labels, identification cards, banknotes, and scientific displays