ALS photography

Question 1

ALS photography

Answer 1

Examination of crime scene using monochromatic light source utilizes the inherent luminescent properties of material

Question 2

ALS

Answer 2

1. Device that provides monochromatic light at specific wavelength
2. Produce filtered/ colored light in one form / another

Question 3

EMS

Answer 3

Short UV : 200 - 280nm
Mid UV: 280 - 315nm
Long UV: 315-400nm
Vis: 400 - 700nm
Near IR: 700 - 1300nm
Medium IR: 1300 - 10000nm

Question 4

Rxns when light strikes a substrate

Answer 4

Absorption
Transmission
Reflection
Fluorescence

Question 5

When white color is perceive

Answer 5

Total reflection

Question 6

When black color is black

Answer 6

Total absorption

Question 7

Fluorescence

Answer 7

Energy absorbed when electrons move from the excited state to the ground state

Question 8

X’tics of fluorescence

Answer 8

1. Have longer wavelength and lower intensity
2. Energy level is very short
   Stimulated by stronger and higher intensity light

Question 9

Phosphorescence

Answer 9

Excited electrons jump to a higher energy level. The electrons have more energy to lose and spend time at different energy levels b/n the excited state and ground state

Question 10

X’tics of phosphorescence

Answer 10

1. Have wide energy level

Question 11

Luminescence

Answer 11

Absorption of light at a specific wavelength by a chem molecule and the emission of light at a longer wavelength

Question 12

X’tics of luminescence

Answer 12

1. Includes both fluorescence and phosphorescence
2. Molecule’s ability to emit light from sources other than heat

Question 13

Chemiluminescence

Answer 13

Emission of light occurs as a result of chem rxns that produce high amounts of energy lost in the form of photons when excited molecules relax to the ground state