The answer to the question is Refraction.
EXPLANATION:
The spoon half dipped inside the water is appeared to be bent. This is due to the optical phenomenon called refraction.
Refraction is the property of light by virtue of which light ray bends away or towards the normal at the point of incidence when it incidents obliquely at the refracting surface.
In the given figure, light rays are coming from air which is optically rarer medium as compared to water. So, the ray, after striking the air-water interface, gets bent towards the normal in the optically denser medium i.e water. It is so because the velocity of light in optically denser medium is less as compared to rarer medium.
We view the object due to the light. As light rays are bent, so the spoon is appeared to be bent.
