[" (c) "pi/2k" .(d) "pi/k],[" 3.A sonometer wire resonates with a given tuning "],[" fork forming standing waves with five antinodes "],[" between the two bridges when a mass of "9kg" is "],[" suspended from the wire.When this mass is "],[" replaced by a mass "M," the wire resonates with "],[" the same tuning fork forming three antinodes for "],[" the same positions of the bridges.The value of "],[" M is "]