Waves and EM Spectrum unit slides 2024-2025

What is a wave?

A wave is a vibration that transfers energy from one place to another.

What are mechanical waves?

Mechanical waves are vibrations that travel through a substance (medium).

What are electromagnetic waves?

Electromagnetic waves are waves that do not require a medium and can travel through a vacuum.

Define longitudinal waves.

Longitudinal waves are waves where the vibrations are parallel to the direction of the wave.

Define transverse waves.

Transverse waves are waves where the vibrations are perpendicular to the direction the wave travels.

What causes compression and rarefaction in longitudinal waves?

In longitudinal waves, compressions are regions where the particles are close together, and rarefactions are regions where the particles are spread apart.

What is the relationship between wavelength and frequency for electromagnetic waves?

As the wavelength decreases, the frequency increases, and vice versa.

What is the formula for wave speed?

Wave speed (v) = frequency (f) x wavelength (λ).

What happens to light when it passes through a prism?

White light is refracted and splits into its constituent colors.

What is dispersion in the context of waves?

Dispersion is the separation of waves into their constituent frequencies when passing through a medium.

List the main groups of the electromagnetic spectrum in order of wavelength.

Radio, Microwave, Infrared, Visible, Ultraviolet, X-Ray, Gamma Ray.

What happens to the speed of waves when they move from a less dense medium to a more dense medium?

The speed of the waves decreases and the wave bends towards the normal.

What is frequency and how is it measured?

Frequency is the number of waves passing a point each second, measured in hertz (Hz).

What is a wavelength?

Wavelength is the distance between two consecutive peaks or troughs of a wave.

What is wave amplitude?

Amplitude is the height of the wave's peak or the depth of its trough from the middle line.

How does sound travel in relation to medium?

Sound is a mechanical wave and travels through air or other mediums.

How does light travel in relation to medium?

Light is an electromagnetic wave and travels through a vacuum or air without requiring a medium.

What is refraction?

Refraction is the change in direction of a wave as it travels from one medium to another.

What is diffraction?

Diffraction is the bending of waves around obstacles or through openings.

What are some common uses of microwaves?

Microwaves are used for satellite communication and in microwave ovens.

What type of wave is represented by sound?

Sound waves are mechanical and longitudinal waves.

What type of wave is represented by light?

Light waves are electromagnetic and transverse waves.

What is an echo?

An echo is a type of reflection where sound waves bounce off a surface and return to the listener.

What is the principle of superposition in the context of waves?

The principle of superposition states that when two or more waves meet, the resultant displacement is the sum of the individual displacements.

What is the normal line in wave reflection?

The normal line is an imaginary line perpendicular to the boundary at the point where the wave hits.

What is the law of reflection?

The angle of incidence is equal to the angle of reflection.

How do we perceive sound intensity?

Sound intensity is related to the amplitude of sound waves; higher amplitude results in louder sounds.

Describe the relationship between energy and frequency of electromagnetic waves.

As frequency increases, the energy of the electromagnetic wave also increases.

What is the significance of ultraviolet light?

Ultraviolet light is used in tanning beds and medical applications to sterilize equipment.

Explain the properties of the electromagnetic waves.

Electromagnetic waves are transverse, do not require a medium, and travel at the speed of light in a vacuum.

What is the formula for frequency based on wave speed and wavelength?

Frequency (f) = wave speed (v) / wavelength (λ).

What is the formula for wavelength in terms of wave speed and frequency?

Wavelength (λ) = wave speed (v) / frequency (f).

What is the formula for velocity in relation to frequency and wavelength?

Wave speed (v) = frequency (f) x wavelength (λ).

List an example of each group in the electromagnetic spectrum.

Radio waves: AM/FM radio; Microwaves: microwave oven; Infrared: remote controls; Visible: sunlight; Ultraviolet: tanning beds; X-Ray: medical imaging; Gamma Ray: cancer treatment.

What is the main difference between transverse and longitudinal waves?

Transverse waves have vibrations perpendicular to the wave direction, while longitudinal waves have vibrations parallel to the wave direction.

What are the main parts of a wave?

The main parts of a wave are the crest (peak), trough (lowest point), wavelength (distance between crests or troughs), and amplitude (height from the rest position to peak or trough).

What is the formula for the period of a wave?

Period (T) = 1 / frequency (f).

What is the behavior of waves at boundaries?

At boundaries, waves can be reflected, refracted, or absorbed.

What is wave reflection?

Wave reflection occurs when a wave bounces off a surface and changes direction.

What is wave refraction?

Wave refraction is the bending of waves as they pass from one medium to another due to a change in speed.

What is wave absorption?

Wave absorption occurs when a wave's energy is taken in by the material it encounters, reducing the wave's amplitude.

What is diffraction?

Diffraction is the bending of waves around obstacles or through openings, significantly affected by the size of gaps relative to the wavelength.

What is the main distinction in diffraction based on gap size?

The amount of diffraction increases when the gap size is comparable to the wavelength; if the gap is much larger, diffraction is minimal.

What is frequency?

Frequency is the number of waves that pass a fixed point in a given period of time, typically measured in hertz (Hz).

What is wavelength?

Wavelength is the distance between two consecutive points of similar phase in a wave, such as crest to crest or trough to trough.

What is the period of a wave?

The period is the time taken for one complete wave cycle to pass a given point, usually measured in seconds.

What is wave velocity?

Wave velocity is the speed at which a wave travels through a medium, calculated as the product of frequency and wavelength.

What is the relationship between frequency, wavelength, and velocity?

Wave velocity (v) = frequency (f) x wavelength (λ).

What is a mechanical wave?

A mechanical wave is a wave that requires a medium (solid, liquid, or gas) to travel through.

What is an electromagnetic wave?

An electromagnetic wave is a wave that can travel through a vacuum and does not require a medium.

Define amplitude of a wave.

Amplitude is the maximum displacement of points on a wave from its rest position, indicating the wave's intensity.

What is the significance of wave frequency in sound?

Higher frequencies in sound waves correspond to higher pitches, while lower frequencies correspond to lower pitches.

How is the speed of sound related to the medium?

The speed of sound varies in different media; it travels fastest in solids, slower in liquids, and slowest in gases.