Answer
$672.0nm$
Work Step by Step
The wavelength emitted by the Enterprise can be determined as
$f^{\prime}=f(1+u/c)$
$\frac{c}{\lambda^{\prime}}=\frac{c}{\lambda}(1+u/c)$
This simplifies to:
$\lambda=\lambda^{\prime}(1+\frac{u}{c})$
We plug in the known values to obtain:
$\lambda=670.3(1+\frac{782.5\times 10^3}{3.0\times 10^8})$
$\lambda=672.0nm$
