A violin has a net string length of 0.68 m, see diagram below A. Sketch the standing waves produced for the 1st and 2nd harmonics and relevant wavelengths. You must specify whether your sketch is a pressure or displacement diagram. (4 marks) B. If the wave speed is 345 m/s, what are the frequencies for the 1st and 2nd harmonics? (6 marks) C. Can the normal human ear hear sounds from the 1st harmonic of the violin? Provide evidence. If you couldn't find the frequency in Part B, use 245 Hz. (4 marks) D. A violinist plays violin with several onlookers around. One of the onlookers moves forward, towards the violinist, from 12 m away to 5 m away from the violinist. What is the ratio (in percentage) of sound intensity due to the two different distances from the violinist? Is intensity increased or decreased? (6 marks) E. To produce a frequency of the same 1st harmonic from Part B, what length is required for a pipe closed at one end? If you couldn't find the frequency in Part B, use 245 Hz.