282103 Light of wavelength $300 \mathrm{~nm}$ in medium $A$ enters into medium $B$ through a plane surface. If the frequency of light is $5 \times 10^{14} \mathrm{~Hz}$ and the ratio of speed in medium $A$ to that is medium $B$ is $\frac{4}{5}$, the absolute refractive index of medium $B$ is.
282103 Light of wavelength $300 \mathrm{~nm}$ in medium $A$ enters into medium $B$ through a plane surface. If the frequency of light is $5 \times 10^{14} \mathrm{~Hz}$ and the ratio of speed in medium $A$ to that is medium $B$ is $\frac{4}{5}$, the absolute refractive index of medium $B$ is.
282103 Light of wavelength $300 \mathrm{~nm}$ in medium $A$ enters into medium $B$ through a plane surface. If the frequency of light is $5 \times 10^{14} \mathrm{~Hz}$ and the ratio of speed in medium $A$ to that is medium $B$ is $\frac{4}{5}$, the absolute refractive index of medium $B$ is.
282103 Light of wavelength $300 \mathrm{~nm}$ in medium $A$ enters into medium $B$ through a plane surface. If the frequency of light is $5 \times 10^{14} \mathrm{~Hz}$ and the ratio of speed in medium $A$ to that is medium $B$ is $\frac{4}{5}$, the absolute refractive index of medium $B$ is.
282103 Light of wavelength $300 \mathrm{~nm}$ in medium $A$ enters into medium $B$ through a plane surface. If the frequency of light is $5 \times 10^{14} \mathrm{~Hz}$ and the ratio of speed in medium $A$ to that is medium $B$ is $\frac{4}{5}$, the absolute refractive index of medium $B$ is.