1402Lab6 - Reflection and Refraction Theory Whenever a wave traveling in some medium encounters an interface or boundary with another medium

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
Reflection and Refraction Theory: Whenever a wave traveling in some medium encounters an interface or boundary with another medium either (or both) of the processes of (1) reflection and (2) refraction may occur if the speed of the wave is different in the two media. If the wave being considered is light the speed of light in any medium is characterized by the index of refraction for the medium, n, where n c/v [1] where c is the speed of light in a vacuum, and v is the speed of light in the medium. (Note that for a vacuum or air n=1.00.) Reflection In reflection, a ray of light traveling in a straight line in medium 1 encounters an interface with medium 2 and the incident ray is reflected (or bounced) backed into medium 1 at the interface of the two media as depicted in Figure 8 – 1. θ r θ i medium 1 Normal medium 2 Figure 8 –1 The normal is a reference point which is always perpendicular to the surface at the “point of impact” where the light is incident onto the surface. If the ray incident on the interface makes an angle θ i with the normal to the surface at the “point of impact” on the interface, the reflected ray will make an angle θ r with the normal from the “point of impact” equal to the incident angle θ i . The relationship between the angles θ i and θ r for all reflections is called the Law of reflection which can be stated in two parts: 1. θ i = θ r , and 2. θ i and θ r are coplanar, (i.e. lie in the same plane.) [2] For light parallel to the principal axis and incident on a spherical (or cylindrical) surface with a radius R, the reflected light will cross the principal axis at a focal point, f, from the vertex (see Figure 8-2) such that f = R/2 [3]
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
where R is the radius of curvature. radius of curvature principal axis f Figure 8 –2 Refraction In refraction, a ray of light traveling in a straight line in medium 1 encounters an interface with medium 2, penetrates the interface and then moves in a straight line in medium 2 as depicted in Figure 8 – 3. If the incident ray originally in medium 1 makes an angle θ 1 with the normal to the surface in medium 1, the refracted ray will make an angle θ 2 with the same normal in medium 2. The relationship between θ 1 and θ 2 for every refraction is called the law of refraction which can be stated in two parts: 1. n 1 sin θ 1 = n 2 sin θ 2 , and [4] 2. θ 1 and θ 2 are coplanar. Normal medium 1 n 2 n 1 medium 2 θ 2 Normal θ 3 θ 2 θ 1 medium 1 n 1 Figure 8 –3 Figure 8–3 represents two interfaces the first is from a lower to higher index of refraction (medium 1 (n 1 ) < medium 2 (n 2 )), and the second is from a higher to low index of refraction (
Background image of page 2
medium 2 (n 2 ) > medium 1 (n 1 )). At the interface of n 1 < n 2 the angle θ 2 will be less than θ 1 in relation to the normal which is in agreement with equation [4]. Likewise when n 2 > n 1 the angle θ 1 will be greater than
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 02/20/2010 for the course PHYS 1402 taught by Professor Staff during the Spring '08 term at UT Arlington.

Page1 / 9

1402Lab6 - Reflection and Refraction Theory Whenever a wave traveling in some medium encounters an interface or boundary with another medium

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online