# 17.1 How Light Behaves at a Boundary

```How
light
behaves at
a
boundary
By Victoria Skinner
17.1 How
Light
law of reflection
*If 2 parallel beams strike a mirror 2 reflected
beams are also parallel
*If a line is perpendicular to a mirror it is the
normal because it is normal to the surface.
reflections
*regular reflection- happens when
light is reflected back to the observer
in parallel beams
*Diffuse reflection- the scattered,
fuzzy reflection from a rough
surface where light is reflected
Refraction of light
Angle of refraction
Angle of refraction- the angle the
refracted ray makes with the normal to
the surface
Optically dense
Optically dense- materials with larger
indices of refraction with respect to other
materials
Snell’s law
• *Snell's law- states that the ratio of sine
of the angle of refraction is a constant
Incident Ray traveling in a less dense medium
index of refraction

• *index of refraction- the ratio of the speed
of light in a vacuum to its speed in a material
*
*The index of refraction often can be measured by
directing a ray of light onto the
substance's surface, measuring
the angle of incidents and angle
of refraction,then using Snell’s
law .
.
problem solving strategies•
•
•
•
•
1.draw a diagram showing 2 media and label
2. Draw the incident ray
3.use protractor
4.use Snell’s law
5.use protractor
• 6.evaluate.
*when solving problems involving
refractions and reflections of light a one
will use a ray diagram .
* when setting up a Snell's law problem
assign symbols for the various
quantities, and check your results.
WORKS CITED
Displacement Sensor Topic: Principle of Regular Reflection Measurement.
OMRON Corporation , 2011. Web. 28 Feb. 2011. &lt;http://www.omronap.co.th/FAQ/ FAQ01367/index.asp&gt;.
Dizzo95. &quot;light refraction.&quot; 12 Nov. 2009. youtube. Web. 28 Feb. 2011.
&quot;Light and Geometric Optics.&quot; OoCities.org. , Oct. 2009. Web. 28
Feb.2011.&lt;http://www.oocities.org/rjwarren_stm/Physics_Notes/
Unit1_Light.html&gt;.
&quot;Refractometers.&quot; Lab Safety Supplies. GHC Specialty Brands,, 2011. Web. 28
Feb. 2011. &lt;http://www.labsafety.com/refinfo/ezfacts/ezf118.htm&gt;.
&quot;Unit 2 Refraction of Light.&quot; Creative Commons Attribution Share-Alike 3.0
License. chemicalparadigms, 2011. Web. 28 Feb. 2011. ht