Complete Question
The complete question is shown on the first uploaded image
Answer:
a
![\theta_(max) =18.38^o](https://img.qammunity.org/2021/formulas/physics/college/6gw1nhhcz7rt6we9l1kkxwdyldotqsbt6i.png)
b
New
![n_(cladding) =1.491](https://img.qammunity.org/2021/formulas/physics/college/8su6axe46p7lp4dh4tawgy4a1w8qkz3vlj.png)
Step-by-step explanation:
From the question we are told that
The refractive index of the core is
![n_(core) = 1.497](https://img.qammunity.org/2021/formulas/physics/college/z2zr11pk9vv31hek9yy8uyrh1kneohq6f8.png)
The refractive index of the cladding is
![n_(cladding) = 1.421](https://img.qammunity.org/2021/formulas/physics/college/q57so3fmaktql4ypz0eoeazjlk00trscyb.png)
Generally according to Snell's law
![n_(core) * sin(90- \theta) = n_(cladding) * sin (90)](https://img.qammunity.org/2021/formulas/physics/college/8o0mpw3nkqcy4epph7cwoz4govfu3u9ooc.png)
Where
is the largest angle a largest angle a ray will make with respect to the interface of the fiber and experience total internal reflection
![\theta_(max) = 90 - sin^(-1) [(n_(cladding))/(n_(core)) ]](https://img.qammunity.org/2021/formulas/physics/college/czt27ob4hyc17bsirhb4h9za3ea7tm37rk.png)
![\theta_(max) = 90 - sin^(-1) [(1.421)/(1.497)} ]](https://img.qammunity.org/2021/formulas/physics/college/jvm83tkjp3jcvfj1ydhvevdc02uh0d007f.png)
![\theta_(max) =18.38^o](https://img.qammunity.org/2021/formulas/physics/college/6gw1nhhcz7rt6we9l1kkxwdyldotqsbt6i.png)
Given from the question the the largest angle is 5°
Generally the refraction index of the cladding is mathematically represented as
![n_(cladding) = n_(core) * sin (90 - 5)](https://img.qammunity.org/2021/formulas/physics/college/aiwlt36n2jz830mpm6954wnsein0fbxy2i.png)
![n_(cladding) =1.491](https://img.qammunity.org/2021/formulas/physics/college/8su6axe46p7lp4dh4tawgy4a1w8qkz3vlj.png)