Question

Lab 08: Reflection and Refraction of Light You will need to run a simulation to do the lab. Answer the following questions as you work through the lab. Write your answers in blue. (Note that we may miss your response if it does not stand out ) Re-load the file in word or PDF format in Canvas before the due date. Overview Light bends when it enters from one medium to another. This bending of light is called Refraction of light. The relationship between the angle of incidence (medium 1) and the angle of refraction (in the medium 2) is given by Snell’s Law: n_1 sin⁡〖θ_1=n_2 sin⁡〖θ_2 〗 〗 Eq. 8.1 Where n_1 is the index of refraction, θ_1 angle of incidence in medium 1; n_2 is the index of refraction, θ_2 is the angle of refraction in medium 2. The angles, θ are measured with respect to the normal to the surface between the two mediums. When light travels from an optically light medium to an optically dense medium, i.e. n_1 n2, the refracted light bends away from the normal. For a certain angle of incidence (called the critical angle, θ_c) the refracted ray will be 90 from the normal. If the angle of incidence is any larger, the ray is totally reflected in medium 1 and no light comes out of medium 2. This is called Total Internal Reflection. For this part of the lab, you will find the critical angle for different sets of boundaries. Select “More Tools” tab . Check the “normal” and “angle” box to view and measure the angles. 1. Set the Medium 1 = Glass (n1 = 1.5); Medium 2 = Air (n2 = 1.0). 2. Start with θ_1=0. Gradually increase θ_1 until the refracted ray, θ_2=90°. This incident angle is the critical angle, θ_c . If you keep on increasing θ_1, there will only be reflected light. In this way, you can figure out the critical angle for different mediums at the boundaries listed in the table below. Table 8.5: Critical angle of different sets of boundaries Medium 1 (n1) Medium 2 (n2) Critical Angle (c) Water Air Glass Air Glass Water Mystery Medium A Air Mystery Medium A Glass 3. Conclusion Question: (i) Based on your observation in the table, what is the condition for total internal reflection? (ii) Is there a total internal reflection if both mediums have same index of refraction (e.g. n_1=n_2 )? Explain your answer.

Answer 1