Exercise 2-13 Micro Lab: The Lethal Effect of Ultraviolet Radiation on Microbial Growth
Ultraviolet radiation is a type of ___________
electromagnetic energy
UV travels in ____
waves
wavelength
the distance between adjacent wave crests and is typically measured in nanometers
Ultraviolet light is categorized into three groups:
1. UV-A
2. UV-B
3. UV-C
UV-A waves
the longest wavelengths, ranging from 315 to 400 nm
UV-B waves
wavelengths between 280-315 nm
UV-C waves
range from 100-280 nm
These wavelengths are most detrimental to bacteria
Why are UV-C waves the most detrimental to bacteria?
Bacteria exposure for more than a few minutes usually results in irreparable DNA damage and death of the organism
What is the most common use of UV light?
to disinfect laboratory work surfaces
gamma rays
The shortest and highest energy wavelengths
Gamma rays start at about ____nm
10^-5
How long are radio waves?
about a kilometer or longer
How long are ultraviolet light waves?
Between 100nm to 380nm
Two cultures used in lab today for comparing UV light
1. Bacillus subtilis
2. Escherichia coli