物理与光电工程学院：《大学物理》课程PPT教学课件（讲稿，英文第三版）Chapter 13 &14 Wave Motion and Sound

Chapter 13 wave motion and sound Chapter 13&14 Wave motion and sound 1. simple Harmonic Waves 2. Wave Equation 3. Energy and Power of Waves 4 Interference of waves 5. Standing Waves 6. The Doppler Effect

Chapter 13 Wave Motion and Sound Chapter 13&14 Wave Motion and Sound 1. Simple Harmonic Waves 2. Wave Equation 3. Energy and Power of Waves 4. Interference of Waves 5. Standing Waves 6. The Doppler Effect

Chapter 13 wave motion and sound Key words: Mechanical wave机械波 Electromagnetic wave电磁波 Transverse wave(横波) Longitudinal wave(纵波) crests(波峰) and troughs(波谷) Sinusoidal wave(正弦波) Traveling( moving, progressive)wave(行波 Standing( (stationary)wave(驻波) Stretched string(拉紧的线、弦线) Angular wave number(角波数 Interference of waves(波的干涉)

Chapter 13 Wave Motion and Sound Key words: Mechanical wave 机械波 Electromagnetic wave 电磁波 Transverse wave（ 横波） Longitudinal wave（纵波） crests (波峰) and troughs (波谷) Sinusoidal wave（正弦波） Traveling (moving, progressive) wave（行波） Standing (stationary) wave（驻波） Stretched string（拉紧的线、弦线） Angular wave number（角波数） Interference of waves（波的干涉）

Chapter 13 wave motion and sound 几个基本概念 定的扰动的传播称为波动,简称为波。 波动是振动的传播过程;振动是激发波动的波源。 机械波机械振动在弹性介质中的传播 波动 电磁波交变电磁场在空间的传播 两 类公机械波的传播需 两具有传播速度 波有传播振动的介质 类母能量传播 的 波日反射 的 不 同/电磁波的传播可不 共折射 之需介质,可在真空中 同干涉 处传播。 特 征日符射

Chapter 13 Wave Motion and Sound 一定的扰动的传播称为波动，简称为波。 波动是振动的传播过程；振动是激发波动的波源。 机械波 电磁波 波动 机械振动在弹性介质中的传播. 交变电磁场在空间的传播. 两 类 波 的 不 同 之 处 ❖机械波的传播需 有传播振动的介质; ❖电磁波的传播可不 需介质，可在真空中 传播。 具有传播速度 能量传播 反射 折射 干涉 衍射 两 类 波 的 共 同 特 征 几个基本概念

Chapter 13 wave motion and sound 813-2 Wave Types p327-331 Classification According to Natures of Matter 1. Mechanical waves 机械波:机械振动以一定速度在弹性介质中由近及远 地传播出去,就形成机械波。 Such as water waves, sound waves all these waves have certain central features: they are governed by Newtons laws, and they can exist only within a material medium(媒质、 介质), such as water,ai, and rock

Chapter 13 Wave Motion and Sound Classification According to Natures of Matter §13-2 Wave Types p327-331 1. Mechanical Waves 机械波: 机械振动以一定速度在弹性介质中由近及远 地传播出去，就形成机械波。 Such as water waves, sound waves. All these waves have certain central features: they are governed by Newton’s laws, and they can exist only within a material medium（媒质、 介质）, such as water, air, and rock

Chapter 13 wave motion and sound 2. Electromagnetic Waves 电磁波: Such as light, radio and television waves, X rays. These waves require no material medium to exist. Its speed through the vacuum iS299792458m/s Examples: Visible and ultraviolet light, radio and television waves, microwaves x rays and radar waves

Chapter 13 Wave Motion and Sound 2. Electromagnetic Waves 电磁波: Such as light, radio and television waves, X rays. These waves require no material medium to exist. Its speed through the vacuum is 299792458m/s. Examples: Visible and ultraviolet light, radio and television waves, microwaves, x rays, and radar waves

Chapter 13 wave motion and sound 3. Matter waves物质波 these waves are associated with electrons protons(质子), and other fundamental particles. The most remarkable property of the matter waves is that wave functions of matter waves are referred to as probability amplitudes of waves. Much of what we discuss in this chapter applies to waves of all kinds. However, for specific examples we shall refer to mechanical waves

Chapter 13 Wave Motion and Sound 3. Matter Waves 物质波 The most remarkable property of the matter waves is that wave functions of matter waves are referred to as probability amplitudes of waves. Much of what we discuss in this chapter applies to waves of all kinds. However, for specific examples we shall refer to mechanical waves. these waves are associated with electrons, protons （ 质 子 ） , and other fundamental particles

Chapter 13 wave motion and sound Classification According to Oscillation Types(P327) 1. Transverse waves横波 The direction of oscillation of medium elements is perpendicular to the direction of travel of the wave。 Compressions and expansions correspond to the crests(波峰) and troughs(波谷) of a transverse waves。 ◆横波:质点振动方向与波的传播方向相垂直的波 (仅在固体中传播)

Chapter 13 Wave Motion and Sound Classification According to Oscillation Types(P327) 1. Transverse Waves 横波 The direction of oscillation of medium elements is perpendicular to the direction of travel of the wave. Compressions and expansions correspond to the crests (波峰) and troughs (波谷) of a transverse waves. ❖横波：质点振动方向与波的传播方向相垂直的波. （仅在固体中传播 ）

Chapter 13 wave motion and sound 09999999999999999x From the figure the wave has the shape of a sine curve or a cosine curve. a typical string element moves up and down continuously as the wave passes

Chapter 13 Wave Motion and Sound From the figure, the wave has the shape of a sine curve or a cosine curve. A typical string element moves up and down continuously as the wave passes

Chapter 13 wave motion and sound 特征1:具有交替出现的波峰 crest和波谷 trough 特征2:各质点振动方向与波的传播方向垂直 振动方向 传播方向 如绳波为横波

Chapter 13 Wave Motion and Sound ➢ 特征1：具有交替出现的波峰crest和波谷trough. ➢ 特征2：各质点振动方向与波的传播方向垂直。 如绳波为横波。 传播方向 振 动 方 向

Chapter 13 wave motion and sound 2. Longitudinal Waves纵波p328 The direction of oscilation of medium elements is parallel to the direction of the waves travel the motion is said to be longitudinal, and the wave is said to be a longitudinal wave ☆纵波:质点振动方向与波的传播方向互相平行的波 (可在固体、液体和气体中传播)

Chapter 13 Wave Motion and Sound 2. Longitudinal Waves 纵波 p328 The direction of oscillation of medium elements is parallel to the direction of the wave’s travel, the motion is said to be longitudinal, and the wave is said to be a longitudinal wave. ❖纵波：质点振动方向与波的传播方向互相平行的波. （可在固体、液体和气体中传播）