Respuesta :

Answer:

[tex]n _{w} = \frac{c}{v} \\ 1.3 = \frac{3 \times {10}^{8} }{v} \\ v = \frac{3 \times {10}^{8} }{1.3} \\ v = 2 \times {10}^{8} \: m {s}^{ - 1} [/tex]