Hello! Please copy what is in yellow into your notebooks and...
18
Hello! Please copy what is in yellow into your notebooks and then complete the handout provided. Check the end of the document, all the answers are in random order (plus an example!)
Transcript of Hello! Please copy what is in yellow into your notebooks and...
Hello! Please copy what is in yellow into your notebooks and then complete the handout provided.
Check the end of the document, all the answers are in random order (plus an example!)
Optics
Have a seat. Get out your notebook and be
ready for notes.☺
Optics – the study of light!
Light Reflects and Refracts!
Lenses and Mirrors
Mirrors and lenses can make things look
bigger or smaller because our eyes always
think that light comes from straight lines,
even if they have been refracted or reflected
Lenses work by RefractionMirrors work by Reflection
Object vs. Image
The object is what you are looking at: the actual thing.
The image is what you THINK you see, it can be
enlarged, reduced, or moved.
OBJECT
IMAGE
Optics Vocab
In order to understand optics, we need to have a good
understanding of vocab.
Inverted: upside down ( )
Upright: right side up ( )
Focal Point: The point where the “rays” will meet.
Optics Key Terms
Real vs Virtual Image
Sometimes real and virtual images are hard to distinguish. There are a couple
of things that REAL images MUST have.
A REAL image MUST obey the following:
• Image that is always inverted
• Image will be projectable (on screen or paper)
• Image will appear PAST the focal point
If all three requirements are not met, the image will be VIRTUAL.
Optics Key Terms
Mirrors and Lenses can be Convergent or Divergent.
Convergent:
light rays that come together
Divergent:
lights rays that spread apart
Lenses
Light that passes through the lens converges.
Produces a real, inverted image
Makes things look bigger
CONCAVE
LENSES
CONVEX
LENSES
• Work by refraction
• Lenses have two sides a real side (right) and a
virtual side (left)
Light that passes through the lens diverges
Produces a virtual, upright image
Makes things look smaller
Draw the pictures
Mirrors
Light that passes through the lens diverges.
Produces a virtual, upright image
Makes things look smaller
CONCAVE
Mirrors
CONVEX
Mirrors
• Work by reflection
• Mirrors have two sides: Real (left side) and a
Virtual ( right side)
•
Light that passes through the mirror converges
Produces a real, inverted image
Makes things look bigger
Draw the pictures
How are lenses and mirrors used?
The
skinny
mirror?
Ray Diagram Key Terms
Focal length, f: The distance from the mirror and the lens and the focal point.
do = object distance from the lens or mirror
di = image distance from the lens or mirror
Magnification, M: The relative size of an image to the actual object.
Ray Diagram Equations
1 = 1 + 1f do di
M= - di
do
1 = 1 - 1do f di
1 = 1 - 1di f do
Solve for f
Solve for distance of object
Solve for distance of image
( ) ( )
( ) ( )
( ) ( )
Solve for Magnification
WATCH OUT!
Notice how the variable you are
solving for is under 1. Well, once
you have your answer, you need to
FLIP it!
(Answer) -1
**All Distances will be in cm!
1 = 1 + 1f do di
Example: Lets say you plugged everything into this equation to solve for
focal length and your answer is 0.1445.
That is NOT the answer!
That means: = 0.1445
So, the final step is to take your answer and find its inverse.
(Answer)-1 = REAL ANSWER
( ) ( )
1f
(0.1445)-1 = 6.92
The focal length is 6.29 cm
Problem solving strategy:
1. Identify your given info (di, do, f)
2. Choose the right equation
3. Fill in the variables
4. Calculate
5. Flip the fraction
6. Solve for magnification
1 + 1 = 1do di f
M= - di
do
1 = 1 - 1do f di
1 = 1 - 1di f do
Solve for f
Solve for distance of object Solve for distance of image
1.5
6
4.166
5
10.08
11
22.5
9
48
0.5
29.33
2
0.25
12.5
0.33
16
24
33
13.3
0.33
0.25
0.5
20
2 12
0.667
13.84
2.25
7.14
2.5
( ) ( )
( ) ( ) ( ) ( )
40
di= 15 cm
do= 10 cm
f= _____
M=_____
Problem solving strategy:
1. Identify your given info (di, do, f)
2. Choose the right equation
3. Fill in the variables
4. Calculate
5. Flip the fraction
6. Solve for magnification
1 + 1 = 1do di f
M= - di
do
1 = 1 - 1do f di
1 = 1 - 1di f do
Solve for f
Solve for distance of object Solve for distance of image
1 + 1 = 1do di f
Solve for f
1 + 1 = 110 15 f
0.1667 = 1/f
( ) ( )
( ) ( ) ( ) ( )
( ) ( )
( ) ( )
FLIP IT!!
0.1667^-1 = f
6 = f
6 cm
M= - di
do
M= - 15
10
M= - 1.5
M= 1.5 x
1.5 x
Problem solving strategy:
1. Identify your given info (di, do, f)
2. Choose the right equation
3. Fill in the variables
4. Calculate
5. Flip the fraction
6. Solve for magnification
1 + 1 = 1do di f
M= - di
do
1 = 1 - 1do f di
1 = 1 - 1di f do
Solve for f
Solve for distance of object Solve for distance of image
1.5
6
4.166
5
10.08
11
22.5
9
48
0.5
29.33
2
0.25
12.5
0.33
16
24
33
13.3
0.33
0.25
0.5
20
2 12
0.667
13.84
2.25
7.14
2.5
( ) ( )
( ) ( ) ( ) ( )
40
