Optics Applications
M. Rocha
Physics 4C
Geometric Optics, The Eye, Microscopes and Telescopes
Lenses (Refraction)
Direction of Refraction
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/4338536/pasted-from-clipboard.png)
Waves bend towards the normal when going from fast to slow
and
away from the normal when going from slow to fast
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/9343084/pasted-from-clipboard.png)
![](http://cochranmath.pbworks.com/f/1366945553/circle-arc-length.gif)
Small angle approximation
Arc Length = Angle in radians x Radius
r = Hypotenuse
Adjacent
Arc Length and The Small Angle Approximation
r
Oposite =
Oposite
L
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/8860154/pasted-from-clipboard.png)
Lenses
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/4338680/pasted-from-clipboard.png)
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/4338682/pasted-from-clipboard.png)
Curved surface of a convex lens causes light rays to converge, magnifying images
Convex Lenses
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/4338692/pasted-from-clipboard.png)
Curved surface of a concave lens causes light rays to diverge, shrinking images
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/4338695/pasted-from-clipboard.png)
Concave Lenses
![](http://2.bp.blogspot.com/-fElj_9DV-Cc/UgIG7vnCtpI/AAAAAAAAB84/EWcp7SmVzdg/s1600/17-caoncave-convex.jpg)
Lenses
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/9343100/pasted-from-clipboard.png)
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/9343103/pasted-from-clipboard.png)
Focal Length
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/9343117/pasted-from-clipboard.png)
Thin Lens Equation
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/5539088/pasted-from-clipboard.png)
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/5539100/pasted-from-clipboard.png)
Virtual vs. Real Images in Convex Lenses
Real Image
Virtual Image
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/9326312/pasted-from-clipboard.png)
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/9326321/pasted-from-clipboard.png)
Virtual Images in Concave Lenses
Virtual Images
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/9343137/pasted-from-clipboard.png)
Checkpoint
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/5539111/pasted-from-clipboard.png)
o = 10cm
i = 30cm
What is the focal length of the lens in the system below?
f = 7.5 cm
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/6061210/Screen_Shot_2019-04-24_at_6.48.02_PM.png)
Checkpoint
If we move the light source (object) to a position 2.5 cm from the lens, in the same setup of the previous checkpoint, what would be the magnification?
f = 7.5 cm
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/6061210/Screen_Shot_2019-04-24_at_6.48.02_PM.png)
Checkpoint
Repeat the previous checkpoint now for a Convex lens?
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/6061210/Screen_Shot_2019-04-24_at_6.48.02_PM.png)
f = -7.5 cm, O = 2.5, i = ?, M = ?
Mirrors (Reflection)
Law of Reflection
The angle of incidence equals the angle of reflection
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/4337997/pasted-from-clipboard.png)
Mirrors
Mirrors are the result of specular reflection
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/4338145/pasted-from-clipboard.png)
Tracing light rays from original, to mirror, to eye allows us to construct the image
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/4338152/pasted-from-clipboard.png)
Convex Mirrors
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/4338316/pasted-from-clipboard.png)
Image from convex mirror is smaller and closer than original
Concave Mirrors
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/4338351/pasted-from-clipboard.png)
Image from concave mirror is larger and farther than original if object close to mirror
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/9343337/pasted-from-clipboard.png)
Concave Mirror Image
O > f (object outside focal length)
Concave Mirror Image
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/9343343/pasted-from-clipboard.png)
O < f (object inside focal length)
Covex Mirror Image
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/9343345/pasted-from-clipboard.png)
f < 0 (always virtual image)
Virtual vs. Real Images in Mirrors
Real Image
Virtual Image
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/9326334/pasted-from-clipboard.png)
The Eye
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/9340332/pasted-from-clipboard.png)
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/9340335/pasted-from-clipboard.png)
Physics of the Eye
Vision Correction
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/9340337/pasted-from-clipboard.png)
(nearsighted)
(farsighted)
Vision Correction
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/9340339/pasted-from-clipboard.png)
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/9340341/pasted-from-clipboard.png)
Myopia Correction
Hyperopia Correction
Microscopes
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/9343382/pasted-from-clipboard.png)
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/9343387/pasted-from-clipboard.png)
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/9340344/pasted-from-clipboard.png)
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/9343400/Screen_Shot_2022-02-16_at_4.19.06_PM.png)
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/9343401/Screen_Shot_2022-02-16_at_4.18.45_PM.png)
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/9343402/Screen_Shot_2022-02-16_at_4.19.20_PM.png)
Total Magnification:
Telescopes
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/9343411/pasted-from-clipboard.png)
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/9340347/pasted-from-clipboard.png)
Telescope Magnification
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/9350428/pasted-from-clipboard.png)
h
Telescope Magnification
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/7328483/pasted-from-clipboard.png)
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/7328543/pasted-from-clipboard.png)
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/7328559/pasted-from-clipboard.png)
Text
Checkpoint
If a telescope has a focal length of 1200 mm. What is the magnification when using a 25 mm eyepiece?
M = 1200 mm/ 25 mm = 48
Telescopes are Light Buckets
The main purpose of telescopes is to collect as much light as possible while maintaining as much detail as possible
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/5445219/pasted-from-clipboard.png)
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/5445220/pasted-from-clipboard.png)
Both the light gathering power and resolution of a telescope increases with the diameter/area of the telescope
Refractors vs. Reflectors
There are two ways to collect light in a telescope. By refraction or by reflection
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/5445241/pasted-from-clipboard.png)
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/5445242/Screen_Shot_2018-11-04_at_8.48.57_PM.png)
Refracting telescopes use a primary/objective lens to collect light by refraction
Reflecting telescopes use a primary/objective mirror to collect light by reflection
Refracting Telescopes
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/5445247/Screen_Shot_2018-11-04_at_8.57.59_PM.png)
Refracting telescopes have many disadvantages:
- The become too long for not that much light collecting area
- Large lenses are extremely expensive to fabricate
- A large lens will sag in the center since it can only be supported on the edges
- Dispersion causes images to have colored fringes
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/5445252/pasted-from-clipboard.png)
![](https://upload.wikimedia.org/wikipedia/commons/e/e9/Refraction_varies_by_frequency.gif)
Refraction of light is frequency dependent
This is because higher frequencies travel slower inside the prism
Slowest
Fastest
Refracting Telescopes Suffer from Chromatic Aberration
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/5445253/pasted-from-clipboard.png)
![](https://upload.wikimedia.org/wikipedia/commons/e/e9/Refraction_varies_by_frequency.gif)
Slowest
Fastest
Refracting Telescopes Suffer from Chromatic Aberration
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/5445255/pasted-from-clipboard.png)
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/5445258/pasted-from-clipboard.png)
Reflecting Telescopes
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/5445263/pasted-from-clipboard.png)
Reflecting telescopes use a parabolic primary mirror to collect light. Light is focused in front of the mirror, how you observed it without blocking the incoming light?
Reflecting Telescopes
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/5445269/pasted-from-clipboard.png)
Reflecting telescopes use either detectors or secondary mirrors to gather or re-direct the focused light from the primary mirror
Concave Mirrors
We use concave mirrors to build telescopes in order to focus the light to the detector
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/7314244/pasted-from-clipboard.png)
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/11190241/pasted-from-clipboard.png)
Telescope Instruments
Cameras and Charged Coupled Devices (CCDs)
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/5448435/pasted-from-clipboard.png)
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/5448437/Screen_Shot_2018-11-05_at_1.00.32_PM.png)
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/5448441/Screen_Shot_2018-11-05_at_1.03.13_PM.png)
![](https://s3.amazonaws.com/media-p.slid.es/uploads/747994/images/5448447/pasted-from-clipboard.png)
Spectrographs
The End
Optics Applications - Physics 4C
By Miguel Rocha
Optics Applications - Physics 4C
Physics 1 - Week 12-13 - Chapters 28-29
- 190