Answer:
[tex]n_{air} =1.0000355[/tex]
Explanation:
from snells law we have following relation
[tex]n' Sin i = n_{air} Sin r[/tex]
[tex] n_{air}[/tex] is refractive index of air
n' - refractive index of air below
i is angle of incidence = 90 - 1.30 = 88.70^o
r is refraction angle
plugging all value in above formula
[tex]1.000293 \times sin 88.7 = n_{air} \times sin 90[/tex]
[tex]n_{air} =1.0000355[/tex]
