Electronic watche keep accurate time uing crytal ocillator. Inide the watch, there i a tiny block of quartz which vibrate. Two oppoite face of the block move alternately toward each other and away from each other. Thi i a caued by a tanding wave in the block. The two oppoite face are at antinode, and the plane halfway between thee two face i at a node. If the two face are 5. 18 mm apart and the peed of ound in quartz i 3. 72 km/, find the frequency of the vibration