Physics Lecture Midterm Exam Reviewer

The Doppler effect refers to the change in frequency of a wave as a result of the relative motion between the wave source and the observer. This phenomenon is observed in various scenarios, such as when an ambulance siren appears to have a higher pitch as it approaches and a lower pitch as it moves away. The statement correctly states that the Doppler effect is the apparent change in frequency caused by relative motion, making the answer true.

The Doppler effect is a phenomenon that occurs when there is relative motion between a source of waves and an observer. When the source moves towards the observer, the frequency of the waves increases, which results in a higher pitch of the sound wave. This is known as the Doppler effect. Therefore, the statement "The Doppler effect increases the frequency of a wave (raises the pitch of a sound wave) when the source moves toward the observer" is true.

The Doppler effect is a phenomenon that occurs when there is relative motion between a source of waves and an observer. When the source moves away from the observer, the frequency of the waves decreases, resulting in a lower pitch of a sound wave. This is because the motion of the source causes the waves to be stretched out, increasing the wavelength and decreasing the frequency. Therefore, the given statement is true.

A wave is a disturbance that propagates through a medium. It carries energy from one point to another without the actual transfer of matter. Waves can be observed in various forms such as sound waves, water waves, and electromagnetic waves. They are characterized by their wavelength, frequency, and amplitude. Waves play a crucial role in many natural phenomena and are essential in fields like physics, engineering, and communication.

Sound is an example of a mechanical wave because it requires a medium, such as air, water, or solids, to propagate. Sound waves are created by the vibrations of an object, which then cause the particles in the medium to vibrate and transfer energy from one point to another. These vibrations travel in the form of compressions and rarefactions, creating a wave-like pattern. Therefore, sound can be classified as a mechanical wave.

Light is an example of an electromagnetic wave. Electromagnetic waves are waves that consist of oscillating electric and magnetic fields, and light is a type of electromagnetic wave that is visible to the human eye. It has properties of both particles and waves and can travel through a vacuum. Light waves have different wavelengths and frequencies, which determine their color and energy. They can be produced by various sources such as the Sun or artificial light sources, and they are essential for vision and various technological applications.

A crest is a point of maximal change in the positive direction, specifically in a transverse wave. It represents the highest point of a wave, where the displacement of the medium is at its maximum in the upward direction. This is in contrast to the trough, which is the lowest point in a wave where the displacement is at its maximum in the downward direction. Therefore, the crest is the correct answer as it accurately describes the point of maximal change in the positive direction in a transverse wave.

A trough is a point of maximal change in the negative direction, specifically in a transverse wave. It is the lowest point in the wave where the displacement of the medium is at its minimum. In a wave, the crest represents the highest point while the trough represents the lowest point. Therefore, the correct answer is trough.

Sound can travel through any medium, but it cannot travel through a vacuum. There is no sound in outer space.

The frequency of a sound wave corresponds to its pitch. Pitch refers to the highness or lowness of a tone. In other words, the pitch of a sound is determined by the frequency of the sound wave. A higher frequency corresponds to a higher pitch, while a lower frequency corresponds to a lower pitch. Therefore, the correct answer is pitch.

Propagation describes the spreading of a disturbance. It refers to the process by which a disturbance, such as a wave or signal, travels through a medium or space. This can occur through various mechanisms, such as mechanical waves propagating through a medium like water or air, or electromagnetic waves propagating through space. Propagation is an essential concept in physics and engineering, as it helps us understand how disturbances and information travel from one point to another.

Sound usually travels fast in gases, faster in liquids, and fastest in solids.\

The statement is true because the upper frequency limit for human hearing is indeed around 18,000 to 20,000 Hz. Frequencies above this range are considered ultrasonic, meaning they are too high for humans to perceive.

Sound is an example of a longitudinal wave because it travels in the same direction as the vibration of particles in the medium it passes through. In a longitudinal wave, the particles of the medium move back and forth parallel to the direction of energy transfer. Sound waves are produced by vibrating objects, such as vocal cords or speakers, and they propagate by causing compressions and rarefactions in the air or other medium they travel through. This characteristic of sound waves makes them a clear example of a longitudinal wave.

A longitudinal wave is a type of wave where the disturbance or oscillation is parallel to the direction of propagation. In other words, the particles of the medium through which the wave is traveling move back and forth in the same direction as the wave is traveling. This is in contrast to a transverse wave, where the disturbance is perpendicular to the direction of propagation. Examples of longitudinal waves include sound waves and seismic waves.

Amplitude refers to the maximum absolute value of a periodically varying quantity. It is a measure of the magnitude or strength of the variation. In the context of sound, amplitude is associated with loudness, intensity, and volume. A higher amplitude indicates a louder sound, while a lower amplitude indicates a softer sound. Therefore, the correct answer is amplitude.

The speed of sound in air increases with temperature.

The statement is true because the lower frequency limit for human hearing is generally accepted to be around 18 to 20 Hz. Frequencies below this range are considered infrasonic, meaning they are below the threshold of what humans can perceive as sound.

As a sound wave propagates, its frequency remains constant. The frequency of a sound wave refers to the number of complete cycles of the wave that occur in one second. This characteristic of sound waves is known as their pitch. So, regardless of the distance traveled or any other factors, the frequency of a sound wave does not change. This is why the statement "The frequency of a sound wave does not change as the sound wave propagates" is true.

Wavelength is inversely proportional to frequency. (λ ∝ 1/ƒ)

A transverse wave is a type of wave in which the disturbance of the wave is perpendicular to the direction of propagation. In other words, the particles of the medium through which the wave travels move up and down or side to side, while the wave itself moves forward. This is in contrast to a longitudinal wave, where the disturbance is parallel to the direction of propagation.

The 6 parameters that describe a periodic wave are cycle, wavelength, frequency, period, amplitude, and velocity or speed.

The question asks for the three types of waves classified by medium. The answer choices provided are mechanical, electromagnetic, and gravitational. Mechanical waves require a medium, such as air or water, to propagate. Electromagnetic waves, on the other hand, can travel through a vacuum and do not require a medium. Gravitational waves are disturbances in the fabric of spacetime caused by accelerating masses. Therefore, the answer choices provided correctly classify waves based on their medium.

The distance between any point on a periodic wave and the next nearest point corresponding to the same portion of the wave is known as the wavelength. It is measured in meters, which is the SI unit for length.

The amplitude of a sound wave corresponds to its intensity, which is the measure of its power density. Intensity refers to the amount of energy transferred by the sound wave per unit of time and per unit of area. On the other hand, loudness refers to the perception of the intensity by the human ear. It is a subjective measure of the sound's perceived volume.

The period refers to the time between successive cycles of a repeating sequence of events. It is measured in seconds, which is the SI unit for period.

Frequency is the number of cycles of a repeating sequence of events in a unit interval of time. It is measured in hertz (Hz), which is the SI unit for frequency.

Intensity is an objective measure of the mean power density of the energy transferred by a wave. It quantifies the amount of energy that is transferred through a unit area perpendicular to the direction of the wave. The SI unit for intensity is watt per square meter or watt per squared meter, which represents the amount of power transferred per unit area.

In longitudinal waves, a compression is a region where the medium is under compression. This means that the particles of the medium are pushed closer together, resulting in a higher density. Condensation can also be used to describe this region, as it refers to the compression of the medium. Therefore, both compression and condensation are valid terms to describe this phenomenon in longitudinal waves.

In longitudinal waves, a rarefaction is a region where the medium is under tension. This is because rarefaction refers to the region where the particles of the medium are spread out, creating a lower density and pressure compared to the surrounding areas. In this region, the particles are pulled apart, causing a tension in the medium. Dilation, on the other hand, refers to the region where the particles are compressed, resulting in an increase in density and pressure. Therefore, the correct answer is rarefaction.