Which of the following function represent a travelling wave? Here a,b and c are constant.
A. `y=a cos (bx) sin (ct)`
B. `y=a sin (bx+ct)`
C. `y=a sin (bx+ct)+a sin (bx-ct)`
D. `y=a sin (bx-ct)`
A. `y=a cos (bx) sin (ct)`
B. `y=a sin (bx+ct)`
C. `y=a sin (bx+ct)+a sin (bx-ct)`
D. `y=a sin (bx-ct)`
Correct Answer – b., d.
A travelling wave is characterized by wave functions of the type `y=f(vt+x) or y=f(vt-x)`. The function of the `sin (bx+ct)` represent a wave travelling in the negative x-direction and the function `y=a si (bx-ct)` a wave in positive x-direction. Hence, the correct choice are (b) and (d).