A long wire PQR is made by joining two wires PQ and QR of equal radii.  PQ has a length 4.8 m and mass 0.06 kg. QR has length 2.56 m and mass 0.2 kg.  The wire  PQR is under a tension of 80 N.  A sinusoidal wave pulse of amplitude 3.5 cm is sent  along the wire PQ from the end P.  No power is dissipated during the propagation of  the wave pulse.