Fill in blank without a word bank (unit is wave nature of light) 1. as water waves travels through a slit barrier, they bend and spread out. this is known as 2. two identical waves will interfere destructively, cancelling one another out, when one lags behind the other by a minimum of wavelength 3. a line along which crests consistently meet crests and troughs constantly meet troughs is called a(n) line 4. for two points sources vibrating in phase producing an interference pattern, the line along the central bisector is a(n) line