A travelling wave y=A sin(kx−ωt+θ) passes from a heavier string to a lighter string. The reflected wave has amplitude 0.5A. The junction of the strings is at x=0. The equation fo the refelcted wave is :
a. y'= 0.5A sin(kx+ωt+θ)
b. y'= -0.5A sin(kx+ωt+θ)
c. y'= 0.5A sin(kx+ωt-θ)
d. y'= -0.5A sin(ωt-kx-θ)