Question 3 (5 Marks) A piece of string is held fixed at one end on an oscillator and hanging vertically downwards. A standing wave can be generated when the oscillator is turned on. The length of the string is 12 cm. If the speed ofthe wave in the string is 2.5 mfs: a) Calculate the frequency of the standing wave that has 2 nodes (including the node at the top}. [2] b) Calculate the frequency that is twice the frequency of the l\" harmonic and discuss whether the string can resonate at a I!"'1 harmonic frequency. [3]