Given data:
* The angle of incidence in the medium A is,
![i=60^(\circ)](https://img.qammunity.org/2023/formulas/physics/college/5xek8k6gjvn7zrdtabb0zgi33h85lbj574.png)
* The angle of refraction in medium B is,
![r=45^(\circ)](https://img.qammunity.org/2023/formulas/physics/college/b5ty6qc5esox7fq9r6ca5xk71nx9kqf1p3.png)
Solution:
According to the Snell's Law,
![\begin{gathered} n_A\sin (i)=n_B\sin (r) \\ (n_B)/(n_A)=(\sin (i))/(\sin (r)) \end{gathered}](https://img.qammunity.org/2023/formulas/physics/college/r9x52xgv4dwfk9m1j6ejpqjs5a7xvcf9nc.png)
where n_B is the refractive index of medium B and n_A is the refractive index of medium B,
Substituting the known values,
![\begin{gathered} (n_B)/(n_A)=\frac{\sin (60^{\circ_{}})}{\sin (45^(\circ))} \\ (n_B)/(n_A)=(0.866)/(0.707) \\ (n_B)/(n_A)=1.225 \end{gathered}](https://img.qammunity.org/2023/formulas/physics/college/prk8ipux5hrqcs347j6gwmb98pvrza9yad.png)
Thus, the ratio of refractive index of medium B to the refractive index of medium A is 1.225.