Given equation , $y = a\sin{(bt - cx)}$ Comparing the given equation with general wave equation $y = a\sin\left( \frac{2\pi t}{T} - \frac{2\pi x}{\lambda} \right),$ We get $b = \frac{2\pi}{T},\ c = \frac{2\pi}{\lambda}$ Dimension of $\ \frac{b}{c}$ $= \frac{2\pi/T}{2\pi/\lambda} = \left\lbrack LT^{- 1} \right\rbrack,$ and other three quantity is dimensionless