[填空题]
(a) AM radio signals have fr(mwy94. 8hvw d np4rvfequencies between 550 )a2i.ju xv kgz1zl*4jkHz and 1600 kHz (kilohertz) and travel with a k12v ij)gazz. ju4xl* speed of $ 3\times10^{8 }$ m/s What are the wavelengths of these signals? m to m(b) On FM, the frequencies range from 88.0 MHz to 108 MHz (megahertz) and travel at the same speed; what are their wavelengths? m to m