Transcript Week3-figs-ppt

Trivia Question
Which “Big Bang Theory” character is from
New Jersey?
(a) Raj Koothrappali
(b) Bernadette Rostenkowski
(c) Howard Wolowitz
(d) Sheldon Cooper
(e) Amy Farrah Fowler
f
e
d
(f) Leonard Hofstadter a b c
(g) Penny
g
Lab 7 layout
The Electromagnetic Spectrum
Is RED or BLUE easier to see at
Night? During day?
Photometric versus Radiometric Units
For detection by
human eye, there is a
‘conversion factor’ to
convert Radiometric
units (eg. Watts) to
Photometric units (eg.
Lumens)
Example Problem
Consider a point source of light with a total power of 1.0W
(a) What is the intensity of the light 2m away from source?
(b) If a detector with an active area of 5x5mm is used to
detect the light, what is the total power incident on the
detector 2m from source?
(c) How does your answer to be (b) change if the detector
is oriented at an angle?
(d) If the sensitivity of the detector is 103 V/W, what voltage
does the detector generate?
(e) With the light source blocked, the measured voltage
output on the detector (due to noise) is 10-6 V. Is the
point light source of (d) detectable?
Example Problem
Using a laser with Wavelength=633nm, beam diameter of
4mm, and total power of 1mW.
(a) Assume light is centered on a 10 by 10mm detector.
How much power is incident on the detector?
(b) If sensitivity is 103 V/W, what is the voltage output of
the sensor?
(c) If the detector is 5mm by 5mm what is the power on the
detector and the detector voltage?
(d) If the detector is 1mm by 1mm what is the detected
power and voltage?
Lab 7 layout