**Text Description:**A cubic block of glass of refractive index \( n = 1.5 \) has its upper face covered with liquid of unknown refractive index. It is observed that when the upper face is illuminated by a diffuse source, i.e., a source providing rays traveling in all directions, rays of light emerge through the side face only at angles \( \theta_t \) greater than 45°. What is the refractive index of the liquid?**Diagram Explanation:**The diagram shows a vertical section of the setup. At the top, there is a layer labeled "LIQUID," indicating the unknown refractive index liquid covering the glass. Above this layer is a "SOURCE," represented with arrows pointing downwards, indicating light coming from a diffuse source illuminating the top face. Below the liquid is a large section labeled "GLASS" indicating the glass block.From the side of the glass, a line is drawn at an angle labeled \( \theta_t \) measuring greater than 45°. This line represents the path of an emerging light ray. The angle with the normal is denoted as \( \theta_t \).

A cubic block of glass of refractive index n = 1.5 has its upper face covered with liquid of unknown refractive index. It is observed that when the upper face is illuminated by a diffuse source, i.e., a source providing rays traveling in all directions, rays of light emerge through the side face only at angles 6 greater than 45°. What is the refractive index of the liquid?

A cubic block of glass of refractive index n = 1.5 has its upper face covered with liquid of unknown refractive index. It is observed that when the upper face is illuminated by a diffuse source, i.e., a source providing rays traveling in all directions, rays of light emerge through the side face only at angles 6 greater than 45°. What is the refractive index of the liquid?