The angle of refraction is 15.6 deg.
When a ray of light passes from medium 1 to medium 2, the refractive index of medium 2 with respect to 1 is the ratio of the absolute refractive index of medium 2 and medium 1
![_1n_2 =(n_2)/(n_1)](https://img.qammunity.org/2019/formulas/physics/high-school/nb119l5vltetrpzt4srgg9vciwed3pwrt3.png)
When light passes from air into diamond, with the given values of refractive indices,
![_an_d =(n_d)/(n_a) =(2.42)/(1.0003) =2.4193](https://img.qammunity.org/2019/formulas/physics/high-school/odzuz3ovg63gqsn81y2qd36s70z88i644m.png)
According to Snell's law,
![image](https://img.qammunity.org/2019/formulas/physics/high-school/d66dnsni2qtj0yw4zjqt6jcgzs178pvau3.png)
The angle of refraction is 15.6 deg