The angle of incidence for a ray of light at a refracting surface of a prism is ${45}^{\mathrm{o}}$. The angle of prism is ${60}^{\mathrm{o}}$. If the ray suffers minimum deviation through the prism, the angle of minimum deviation and refractive index of the material of the prism respectively, are:

• A

  ${45}^{\mathrm{o}};\frac{1}{\sqrt{2}}$
• Correct answer
  B

  ${30}^{\mathrm{o}};\mathrm{ }\sqrt{2}$
• C

  ${45}^{\mathrm{o}};\sqrt{2}$
• D

  ${30}^{\mathrm{o}};\frac{1}{\sqrt{2}}$

Hence, the correct answer is option: 'B'.