16) Infated And Uv Light

Question 1

Infrared radiation

Answer 1

Electromagnetic wave

Maximum is at 1mm
Radio wave limit

Minimum is at 760nm
Visible light limit

Question 2

Regions of IR

Answer 2

near IR
lander from 760nm to 2.5 Um

Mid IR
lander from 2.5um to 50 I’m

Far IR
Lander from 50 um to 1mm

Question 3

Sources of IR

Answer 3

All heated bodies:

The sun
Temp is 6000°c
50% of emissions is in the IR range

Incandescent lamps
Temp is 2500°c
Maximum emission is at 1500-2500 nm

Human body at 9500nm

Question 4

Detectors of IR

Answer 4

Converters of heat or electromagnetic energy into electrical energy d

Thermophiles are non selective
Photoresistors are Selective

The human eye is insensitive to IR

Question 5

Properties of IR

Answer 5

Strong absorption in water

Ordinary glass only transmits near IR RAD

Weak scattering in matter

Penetrates 2cm in tissue

Question 6

Medical uses of IR

Answer 6

In physiotherapy it speeds up blood circulation and metabolism

Thermography provides thermal images of the body

Question 7

Thermography

Answer 7

The IR radiation is measured and used to determine surface temp of the body

Thermal relief is distribution of temp on the body surface

Question 8

Uv radiation

Answer 8

Electromagnetic wave

Minimum is at 10nm
X ray range

Maximum is at 380nm
At the visible

Question 9

Regions of UV

Answer 9

Longwave
From 380-200 JM

Shortwave
200 to 10nm

Question 10

Medical zones

Answer 10

Long wave is divided into 3 sections

Zone A
From 380-315
Zone B 
From 315-280
Zone c
From 280-200

Question 11

Sources of Uv

Answer 11

The sum emits uv radiation
Only uva and uvb penetrate the atmosphere to the earths surface

Gas discharge in mercury lamps

Question 12

Detectors

Answer 12

Converters of electromagnetic to electrical

Photo resistors
Photocells

The human eye is insensitive to UV rad

Question 13

Properties

Answer 13

Ionising effect

Causes oxidation and reduction

Causes fluorescence

Strong absorption in ordinary glass

Question 14

Effects of uv on the human body

Answer 14

Weak penetration into the human skin

Overexposure to the eye causes inflammation

Overexposure to skin causes skin cancer and ageing

It stimulates vitamin d production that is beneficial to health

Question 15

Effects of UVA RADIATION

Answer 15

Helps prevent rickets in kids due to photochemical production oF vitamin D

Stimulates production of melanin in skin

Question 16

Effects of UVB

Answer 16

Causes reddening if skin and carcinogenic effects

Question 17

Effects of UVC

Answer 17

Strong germicidal effect and strong carcinogenic effect