2C2 Waves and Their Applications

Question 1

Define:

wave

Answer 1

A disturbance that transfers energy through a medium or space.

Waves can be mechanical (requiring a medium like water or air) or electromagnetic (which do not require a medium and can travel through a vacuum, such as light and radio waves).

Question 2

What is amplitude in a wave?

Answer 2

The maximum distance of particles from their equilibrium position.

It determines the wave’s energy; higher amplitude waves carry more energy.

Question 3

How does amplitude affect wave energy?

Answer 3

Higher amplitude waves carry more energy.

The energy of a wave is directly proportional to the square of its amplitude.

Question 4

Fill in the blank:

The rate at which a wave moves through a medium is called _____ _____.

Answer 4

wave speed

Wave speed depends on both the frequency and wavelength of the wave, and it can be calculated using the formula: Speed = Frequency × Wavelength.

Question 5

True or False:

Amplitude affects the speed of the wave.

Answer 5

False

The speed of a wave is determined by the properties of the medium, not its amplitude.

Question 6

True or False:

The wave speed is constant for all waves.

Answer 6

False

Wave speed varies depending on the medium through which the wave is traveling (e.g., sound travels faster in water than in air).

Question 7

What is the formula for calculating wave speed?

Answer 7

𝑣 = 𝑓𝜆

Where v is wave speed, f is frequency, and λ (lambda) is wavelength.

Question 8

What is the distance between two consecutive wave peaks or troughs?

Answer 8

Wavelength

Wavelength is typically denoted by the symbol λ (lambda) and is measured in units of length, such as meters or nanometers.

Question 9

What is the period of a wave?

Answer 9

The time it takes for one complete cycle or oscillation.

Period is the inverse of frequency—high frequency waves have shorter periods.

Question 10

True or False:

A wave with higher frequency has lower energy.

Answer 10

False

Higher frequency waves, like gamma rays, carry more energy compared to lower frequency waves like radio waves.

Question 11

Fill in the blank:

Frequency in a wave is the number of complete cycles or ________ a wave makes per unit of time.

Answer 11

oscillations

Frequency is typically measured in hertz (Hz), where 1 Hz equals one cycle per second.

Question 12

Fill in the blank:

If the frequency of a wave increases, the ________ decreases.

Answer 12

wavelength

This is due to the inverse relationship between frequency and wavelength.

Question 13

If a wave travels at 50 m/s and has a wavelength of 5 meters, what is its frequency?

Answer 13

10 Hz

The frequency is found by rearranging the formula to 𝑓 = 𝑣 / 𝜆, dividing wave speed by wavelength.

Question 14

A sound wave travels at 340 m/s. If its frequency is 680 Hz, what is its wavelength?

Answer 14

0.5 meters

To find the wavelength, use the formula 𝜆 = 𝑣 / 𝑓, dividing the wave speed by the frequency.

Question 15

What is the relationship between wavelength and frequency?

Answer 15

They are inversely proportional.

As wavelength increases, frequency decreases, and vice versa, according to the equation c = λf, where c is the speed of light, λ is the wavelength, and f is the frequency.

Question 16

What happens to the energy of a wave if its frequency increases?

Answer 16

It increases.

Energy is directly proportional to frequency, so higher frequency waves have more energy.

Question 17

How are frequency and period related?

Answer 17

Period is the inverse of frequency.

Period and frequency are inversely related: the period (T) is the time it takes for one complete cycle, calculated as T = 1/f, where f is the frequency.

Question 18

Fill in the blanks:

Transverse waves move ________ to the wave direction, while longitudinal waves move _______ to it.

Answer 18

perpendicular, parallel

This difference affects the types of waves, such as light being transverse and sound being longitudinal.

Question 19

True or False:

Water waves are purely transverse waves.

Answer 19

False

Water waves combine transverse (up-and-down motion) and longitudinal (back-and-forth motion) movements, making them surface waves.

Question 20

What type of waves can be polarized?

Answer 20

Transverse waves

Only transverse waves, like light, can be polarized because their oscillations are perpendicular to wave direction.

Question 21

What are electromagnetic waves?

Answer 21

Waves that do not require a medium and can travel through a vacuum.

These waves consist of oscillating electric and magnetic fields and include visible light, microwaves, and X-rays.

Question 22

Fill in the blank:

________ waves have the longest wavelengths in the electromagnetic spectrum.

Answer 22

Radio

Radio waves can have wavelengths ranging from millimeters to kilometers.

Question 23

What are ultraviolet rays?

Answer 23

Waves with wavelengths shorter than visible light but longer than X-rays.

UV rays can cause sunburn and are blocked by sunscreen.

Question 24

What is the visible spectrum?

Answer 24

The portion of the electromagnetic spectrum visible to the human eye.

It ranges from approximately 380 nm (violet) to 700 nm (red).

Question 25

What is the wavelength **range** for visible light?

Answer 25

400 nm and 700 nm. ## Footnote This range is the only part of the electromagnetic spectrum *visible* to the human eye.

Question 26

# True or False: Infrared radiation has a **higher** frequency than visible light.

Answer 26

False ## Footnote Infrared has **lower** frequencies and longer wavelengths than visible light.

Question 27

What determines the **color** of visible light?

Answer 27

The **wavelength** of the light. ## Footnote Shorter wavelengths correspond to violet and blue, while longer wavelengths correspond to red.

Question 28

What is the **order of colors** in the visible spectrum from longest to shortest wavelength?

Answer 28

* Red * Orange * Yellow * Green * Blue * Indigo * Violet ## Footnote This sequence can be remembered using the acronym **ROYGBIV**. Each color corresponds to a specific range of wavelengths within the visible spectrum.

Question 29

Which color has the **shortest** wavelength in the visible spectrum?

Answer 29

Violet ## Footnote Violet light has the shortest wavelength in the visible spectrum, typically around 380–450 nm.

Question 30

Which color has the **longest** wavelength in the visible spectrum?

Answer 30

Red ## Footnote Red light has wavelengths around *620-750 nm*.

Question 31

# Fill in the blank: Light wave is an **example** of a/an \_\_\_\_\_\_\_\_ wave.

Answer 31

electromagnetic ## Footnote *Electromagnetic waves*, such as light, do not require a medium and can travel through space.

Question 32

What are the **two components** of light waves?

Answer 32

* Electric fields * Magnetic fields ## Footnote These fields *oscillate* perpendicularly to each other and to the direction of wave propagation.

Question 33

What is the **speed** of light in a vacuum?

Answer 33

Approximately **3.00 × 10⁸ m/s**. ## Footnote This value is equivalent 186,000 mi/s. This speed is a fundamental constant in physics, denoted by the symbol **c**.

Question 34

# True or False: Light **requires a medium** to propagate.

Answer 34

False ## Footnote Unlike sound waves, which need a material medium (air, water, or solids), light can travel through the vacuum of space due to its oscillating electric and magnetic fields, which sustain each other.

Question 35

# Fill in the blank: \_\_\_\_\_\_ exhibits both wave and particle **properties**.

Answer 35

Light ## Footnote This duality is a cornerstone of **quantum mechanics**.

Question 36

What is a **photon**?

Answer 36

A quantum, or particle, of **light energy**. ## Footnote They are massless particles that carry energy proportional to their frequency.

Question 37

What **equation** relates the energy of a photon to its frequency?

Answer 37

E = h x f ## Footnote Here, E is energy, h is Planck's constant (6.26x10^-34^), and f is the frequency.

Question 38

What are **mechanical waves**?

Answer 38

Waves that **require a medium** to travel. ## Footnote These waves cannot travel through a vacuum because they rely on the vibration of particles in a medium.

Question 39

# True or False: Mechanical waves **can travel** through a vacuum.

Answer 39

False ## Footnote Mechanical waves *require a medium*, like air, water, or solid substances, to propagate.

Question 40

# Define: seismic waves

Answer 40

Energy waves traveling through **Earth's interior** and **surface**. ## Footnote *Seismic waves* are generated by earthquakes, volcanic activity, or explosions and are classified as *body waves* (P-waves & S-waves) and *surface waves* (Love & Rayleigh waves).

Question 41

What **determines** the pitch of a sound?

Answer 41

The **frequency** of the sound wave. ## Footnote High-frequency sound waves produce high-pitched sounds, while low-frequency waves produce low-pitched sounds.

Question 42

# Fill in the blank: The **fastest type** of seismic wave is the ______ wave.

Answer 42

P ## Footnote *Primary (P) waves* are compressional waves that travel the **fastest** and move through both solid and liquid layers of Earth.

Question 43

# Fill in the blank: The **process** by which a material takes in light energy and converts it into heat is called \_\_\_\_\_\_\_\_.

Answer 43

absorption ## Footnote Dark-colored objects absorb more light, converting it into heat energy.

Question 44

What is the **speed of sound** in air?

Answer 44

Approximately **343 m/s** at room temperature. ## Footnote The speed of sound depends on the **medium** (e.g., air, water, or solid materials) and temperature. It is faster in warmer air and in denser media.

Question 45

What **type of wave** is sound?

Answer 45

Longitudinal (compression) wave ## Footnote In this kind of wave, particles move back and forth in the same direction as the wave, creating **compressions** and **rarefactions**.

Question 46

How is sound intensity **measured**?

Answer 46

In **decibels** (dB). ## Footnote **Decibels** are a logarithmic unit used to measure sound intensity. A 10 dB increase represents a tenfold increase in intensity.

Question 47

What does the human ear perceive as **louder** sound?

Answer 47

A sound with **greater** amplitude. ## Footnote As the amplitude of a sound wave increases, the energy transferred through the medium increases, making the sound appear louder to the human ear.

Question 48

What is a **compression** in a sound wave?

Answer 48

A **region** where particles are closest together. ## Footnote It occurs when the particles of the medium are compressed, creating areas of *high pressure* in the sound wave.

Question 49

# True or False: The loudness of sound is directly **related** to its frequency.

Answer 49

False ## Footnote Loudness is related to the **amplitude** of the sound wave, not its frequency. High amplitude means louder sound, regardless of pitch.

Question 50

What **happens** to the pitch of a sound as its frequency increases?

Answer 50

It becomes **higher**. ## Footnote As the frequency of sound increases, the number of vibrations per second increases, leading to a higher-pitched sound.

Question 51

What is the **threshold** of hearing?

Answer 51

The **quietest** sound detectable, typically at **0 dB**. ## Footnote It *corresponds* to the lowest sound intensity that can be perceived, below which sound is inaudible.

Question 52

# Fill in the blank: A sound with a **low** frequency is perceived as a \_\_\_\_\_\_ pitch.

Answer 52

low ## Footnote Low-frequency sound waves produce lower-pitched sounds, such as those from a bass drum or thunder.

Question 53

What is the **Doppler effect**?

Answer 53

The **change in frequency or wavelength due to motion** of the observer or source. ## Footnote This effect is *noticeable* with sound, like a siren changing pitch as it passes.

Question 54

# True or False: The Doppler effect **only** applies to sound waves.

Answer 54

False ## Footnote The Doppler effect applies to **all** types of waves, including light waves in astronomy.

Question 55

What **happens** to the pitch of a sound as the source approaches an observer?

Answer 55

It increases. ## Footnote According to the Doppler effect, this occurs because the sound waves are compressed, increasing their frequency.

Question 56

What **happens** to the frequency of a sound as the source moves away from the observer?

Answer 56

It decreases. ## Footnote As the sound source moves away, the waves are stretched, decreasing the frequency and lowering the pitch.

Question 57

What is **polarization** of light?

Answer 57

The **alignment of light waves** in a specific direction. ## Footnote For example, polarized sunglasses use this principle to block horizontally polarized light, which significantly reduces glare from reflective surfaces like water, glass, or roads, enhancing visibility and comfort.

Question 58

How does light **interact** with matter?

Answer 58

It can be **reflected, absorbed**, or **transmitted**. ## Footnote These interactions *depend* on the material and the light’s wavelength.

Question 59

What is **refraction**?

Answer 59

The **bending of light** as it passes from one medium to another. ## Footnote Refraction occurs due to a change in the speed of light.

Question 60

What is **reflection**?

Answer 60

The way that **light bounces** when it hits a surface. ## Footnote It occurs when light interacts with a boundary and does not pass through it, such as when a *mirror* reflects light.

Question 61

What are **optical fibers** an example of?

Answer 61

Total internal reflection ## Footnote Optical fibers use *total internal reflection* to transmit light signals over long distances without significant loss.

Question 62

# True or False: Total internal reflection **occurs** when the angle of incidence is less than the critical angle.

Answer 62

False ## Footnote Total internal reflection only occurs when the angle of incidence exceeds the critical angle.

Question 63

# True or False: Light travels **faster** in glass than in air.

Answer 63

False ## Footnote Light **slows** down in denser mediums like glass due to interactions with the material.

Question 64

What causes a **rainbow**?

Answer 64

Refraction, dispersion, and reflection of **light** in water droplets. ## Footnote Different wavelengths are refracted by different amounts, separating the colors.

Question 65

# Fill in the blank: \_\_\_\_\_\_\_\_ is the **splitting** of white light into its constituent colors when passing through a prism.

Answer 65

Dispersion ## Footnote Dispersion occurs because *different* wavelengths of light refract by different amounts.

Question 66

# True or False: Violet refracts the **most** during dispersion.

Answer 66

True ## Footnote Violet light has the *shortest* wavelength and *highest refractive index*, causing it to bend more than other colors.

Question 67

# Define: Diffraction

Answer 67

The **bending of light waves** around obstacles or through small openings. ## Footnote This phenomenon explains effects like the spreading of sound around corners or the patterns observed in light passing through narrow slits.

Question 68

What is **interference**?

Answer 68

The **interaction** of two or more waves that results in a new wave pattern. ## Footnote Interference can be *constructive* (amplifying) or *destructive* (canceling).

Question 69

# True or False: Destructive interference **occurs** when the crest of one wave overlaps with the crest of another.

Answer 69

False ## Footnote Destructive interference occurs when a crest overlaps with a trough, canceling the wave out.

Question 70

What is the **principle of superposition**?

Answer 70

When waves overlap, the resulting wave is the **sum** of their displacements. ## Footnote This principle explains phenomena like standing waves and interference patterns.

Question 71

# Fill in the blank: Light waves vibrating in **all** directions are converted into a single plane through \_\_\_\_\_\_\_\_.

Answer 71

polarization ## Footnote Polarized light is often used to reduce glare.

Question 72

What is **scattering**?

Answer 72

The **redirection** of light by particles in its path. ## Footnote Rayleigh scattering *explains* why the sky appears blue, as shorter wavelengths scatter more.

Question 73

What is the **term** for light passing through a material?

Answer 73

Transmission ## Footnote Transparent materials like **glass** allow light to *pass through* with minimal scattering.

Question 74

# True or False: Scattering **only** occurs in the atmosphere.

Answer 74

False ## Footnote Scattering can occur in any medium containing particles that interact with light.

Question 75

What **causes** the red color of sunsets?

Answer 75

Scattering of **shorter wavelengths**, leaving longer ones like red. ## Footnote At sunset, sunlight passes through more atmosphere, scattering blue light away.

Question 76

What is a **plane mirror**?

Answer 76

A mirror with a **flat** surface. ## Footnote These mirrors reflect light to form an image that is the same size as the object but reversed.

Question 77

What is the **focal point** of a plane mirror?

Answer 77

It **doesn't** have a focal point. ## Footnote They reflect light without converging or diverging it, so they don’t have a real focal point.

Question 78

What are *three* **main types** of of mirrors?

Answer 78

1. Plane 2. Convex 3. Concave ## Footnote Light interacts differently with each type of mirror.

Question 79

What is a **convex mirror**?

Answer 79

A mirror with a curved surface that bulges **outward**. ## Footnote These mirrors diverge light rays, which results in smaller, virtual, and upright images.

Question 80

What is a **concave mirror**?

Answer 80

A mirror with a curved surface that curves **inward** like a bowl. ## Footnote These mirrors can converge light rays, forming real or virtual images depending on the object’s position relative to the focal point.

Question 81

# True or False: Convex mirrors **always** form virtual images.

Answer 81

True ## Footnote Convex mirrors always form virtual, diminished images regardless of the object's position.

Question 82

In which **applications** are concave mirrors generally used?

Answer 82

Shaving mirrors and telescopes. ## Footnote Concave mirrors are used to **magnify** images, such as in shaving mirrors or optical telescopes for better focus on distant objects.

Question 83

What is a **lens**?

Answer 83

A **transparent** object that refracts light to form an image. ## Footnote Lenses can converge or diverge light depending on their *shape* (convex or concave).

Question 84

What is a **concave** lens?

Answer 84

A lens that is **thinner** in the middle than at the edges. ## Footnote Concave lenses diverge light rays, forming a virtual, upright, and diminished image.

Question 85

# True or False: Convex lenses **always** form real images.

Answer 85

False ## Footnote Convex lenses can form both real and virtual images depending on the position of the object relative to the focal point.

Question 86

# Fill in the blank: \_\_\_\_\_\_ lenses are used in **microscopes**.

Answer 86

Convex ## Footnote These lenses magnify small objects by converging light and forming a magnified image.

Question 87

What are the **two main types** of signals used in information systems?

Answer 87

1. Analog Signal 2. Digital Signal ## Footnote **Analog Signal**: A continuous signal that varies over time. **Digital Signal**: A discrete signal using binary values (0s and 1s).

Question 88

What type of signal is used in **modern communication systems**?

Answer 88

Digital signals ## Footnote Most modern communication systems use *digital signals* because they are more reliable, less affected by noise, and easier to store and transmit.

Question 89

What are the **advantages** of digital signals?

Answer 89

* Less interference and noise resistance. * Easy storage and transmission. * More efficient data compression. * Better security through encryption. ## Footnote Digital signals maintain quality over long distances and allow advanced error detection and correction.

Question 90

What are the **advantages** of analog signals?

Answer 90

* More natural and continuous representation. * High fidelity for sound and image quality. * No need for conversion in natural signals. ## Footnote Analog signals, like those in vinyl records and old TVs, capture fine details but degrade over long distances due to noise.

Question 91

# True or False: Analog signals are **more resistant** to noise than digital signals.

Answer 91

False ## Footnote Analog signals **degrade** over distance and are easily affected by interference, while digital signals maintain integrity through encoding and error correction.