11 Electromagnetic waves Flashcards
Electromagnetic spectrum
- radio
- microwaves
- Infrared
- visible light
- UV light
- X-ray
- Gamma ray
Radio
- radio
- TV transmission
- bluetooth
Microwaves
- microwave oven
- wifi
- satellite
- mobile phone
Infrared
- remote control
- night vision
- electric grill
Visible light
- photography
- vision
UV light
- sterilizing water (kill bacteria)
- detecting fake bank notes
X-ray
- medical imaging
- security scanning
Gamma ray
- sterilizing food and medical equipment
- detect cancer
Speed of light
3 x 10^8 m/s
White light
combination of all frequency light produces white color light
Monochromatic light
single frequency light
Critical Angle
Angle of incident that produces 90º to angle of refraction
(light is refracted along the boundary)
refractive index medium (n)
speed of light in a vacuum (3x10^8) / speed of light in medium
n (air)
1
Total internal reflection
angle of incidence = angle of reflection
All light reflect into the same median rather than refract to upper medium
relationship between angle I and angle r from medium 1 to medium 2
n1sinθ1 = n2sinθ2
or
n = 1/sin C –> C = critical angle
Convex / converging lens
long-sighted eye
: reduces focal length
Concave / diverging lens
[cave for short people –> diving in cave]
short-sighted eye
: increases focal length
Virtual image
- magnifying glass
- mirror
- upright
- same shape / size?
- extent real ray backward
Real image
- formed on screen
- upside down
- smaller
- real ray cross to form image
