                                                     7—12  b         
                                                                                                                              
           7—12  a                                      5×10－7                                                                              
                                                                                                                        

          T           v                          Hz             
                
  V      v   λ                       
                             
                                                            c   c                       c      
                                            x   r     7—8                 
                                                                               c    
                 
                                                                         
                                                                                                                               
   
                                                          简谐运动                                simple harmonic motion
                                                                        周期                                      period，T
                                                                       频率                                      fnquency, v
                                                                        赫兹                                       hertz
                                                                        振幅                                      amplitude
                                                               正弦曲线                                sinusoidal
                                                                横波                                      transverse wave
                                                                波长                                      wavelenght , λ
                                                             波速                                      wave velocity，V
                                                                 纵波                                      longitudinal wave
                                                                        声                                         sound
                                                                  音调                                      pitch
                                                            声带                                 vocal cords                                        
                                                         耳鼓膜                                  eardrum
                                                       电磁波                                  electromagnetic wave
                                                     光速                                         speed of light, c
                                                        无线电波                                   ridio waves
                                                        微波                                         microwaves
                                              红外线                                      ultraviolet
                                                      可见光                                      isible light
                                               紫外线                                      ultraviolet
 X                                                         X射线                                      X—rays
    γ                                         伽马射线                                   gamma rays
                                                     光压                                          pressure of light
                                  电磁波的强度                             intensity of an electromagnetic wave
                                     电磁波的能量                             energy of an electromagnetic wave
                                                    波阵面                                      wavefront 
                                                       子波                                          wavelet
                                                        干涉                                          interference
                                                           衍射                                         diffraction
                                                  干涉条纹                                   interference fringes
                                                    衍射条纹