# Refraction and Lenses - Mission RL3 Detailed Help

 The diagrams below show light refracting at the boundary between material 1 and material 2. In which of these cases is material 1 the more optically dense of the two media? Include all that apply.
 The Direction of Bending: Refraction is the bending of the path of light as it passes across the boundary between two media. The direction of refraction is dependent upon the relative speed at which light moves within the two media. The rules are: When light passes from a medium in which it travels faster into a medium in which it travels slower, the light ray will refract towards the normal line. When light passes from a medium in which it travels slower into a medium in which it travels faster, the light ray will refract away from the normal line.
 Optical Density and the Speed of Light: The speed at which light travels through a medium is dependent upon the optical density of that medium. Light travels fastest in media that are least optically dense.
 This question will require your best thinking - as well as a good understanding and some mental organization. As for the understanding, the content which must be understood to be successful is stated in the two Know the Law sections above. Carefully inspect each diagram and observe the direction that light refracted - either towards or away from the normal. From the direction of bending, identify which medium is the one in which light travels slowest. This is the medium that is most optically dense. Repeat for each diagram in order to complete the question. Take your time and use your noodle (that's your brain).