UV

Question 1

SI symbol for radiant energy?

Answer 1

Radiant energy
Symbol Q

Question 2

SI symbol and units for radiant exposure?

Answer 2

Radiant exposure
Symbol H
Units J/m^2

Question 3

SI symbol and units for irradiance?

Answer 3

Irradiance
SI symbol E
Units W/m^2

Differs from intensity, because it is directional (power incident from a given direction), rather than total power through a surface.

Question 4

SI symbol and units for luminous power?

Answer 4

SI symbol Q
Units lm

Photometric equivalent of power

Question 5

SI symbol and units for illuminance?

Answer 5

Illuminance
SI symbol E
Units lm/m^2

Photometric equivalent of irradiance

Question 6

Two classes of detectors for UV and their advantages

Answer 6

Thermopile:
Flat response over wide bandwidth

Photoelectric/solid state:
high sensitivity

Question 7

What is the thermal daily limit specified in CAORW regs?

Answer 7

10 kJ/m^2
UVA radiant exposure over 8 h

Question 8

What is the photochemical daily limit specified in CAORW regs?

Answer 8

30 J/m^2
EFFECTIVE radiant exposure over 8 h
ICNIRP weighted

Question 9

What is the range of UV in tissue?

Answer 9

~0.1 mm

Question 10

Two UV sources

Answer 10

Fluorescent lamps - poor stability
LEDs

Question 11

What is UV used to treat?

Answer 11

UVB for Vitamin D deficiency
UVA + psoralen / UVB for psoriasis

Question 12

What is psoriasis?

Answer 12

Fast cell turnover => suppress to treat