b
\(\mathrm{y}(\mathrm{x}, \mathrm{t})=0.005 \cos (\alpha \mathrm{x}-\beta \mathrm{t})\) (Given)

Comparing it with the standard equation of wave

\(\mathrm{y}(\mathrm{x}, \mathrm{t})=\mathrm{a} \cos (\mathrm{kx}-\omega \mathrm{t})\) we get

\(\mathrm{k}=\alpha\) and \(\omega=\beta\)

\(\therefore \frac{2 \pi}{\lambda}=\alpha \quad\) and \(\quad \frac{2 \pi}{\mathrm{T}}=\beta\)

\(\therefore \alpha=\frac{2 \pi}{0.08}=25 \pi \quad\) and \(\quad \beta=\frac{2 \pi}{2}=\pi\)