PHASES OF LAB TESTING (Spectrophotometer)

Question 1

Parts of the spectrophotometer

Answer 1

1. Light source
2. Entrance slip
3. Monochromator
4. Exit slip
5. Cuvette
6. Photodetector
7. Read-out device

Question 2

visible spectrum range

Answer 2

400 - 700 nm

Question 3

invisible spectrum range

Answer 3

below 400 nm (ultraviolet)
above 700 ( infrared)

Question 4

explain beer’s law

Answer 4

the concentration of a substance is directly proportional to the amount of light absorbed while inversely proportional to the logarithm of transmitted light

Question 5

2 types of spectrophotometer

Answer 5

single or double beam

Question 6

provides the incident light for the system

Answer 6

light source

Question 7

most common source of light in the visible and IR regions

Answer 7

tungsten iodide lamp or incandescent

Question 8

best light source for uv spectrum

Answer 8

deuterium lamps
mercury lamps

Question 9

best light source for IR spectrum

Answer 9

silicon carbide

Question 10

isolates light of a specific wavelength from the light source

Answer 10

monochromator

Question 11

most commonly used monochromator and consist of manny parallel groves etched on the polished surface

Answer 11

difraction grating

Question 12

kind of monochromator that refracts a narrow beam to the denser glass

Answer 12

quartz prism or glass prism

Question 13

holds the solution to measured

Answer 13

cuvette (sample cell)

Question 14

converts the transmitted radiant energy into a qualitative amount of eletrical energy

Answer 14

photodetectors

Question 15

least expensive but still durable kind of photodetector

Answer 15

photocell (barrier-layer cell)

Question 16

it is composed of a fil of light sensitive material, frequently selenium, on a plate of iron

Answer 16

photocell (barrier-layer cell)

Question 17

type of detector mainly used in filter photometers

Answer 17

photocell (barrier-layer cell)

Question 18

they are temperature sensitive and non linear in very high and low levels of illumination

Answer 18

photocell (barrier-layer cell)

Question 19

contains a cathode and an anode in a glass case

Answer 19

phototube

Question 20

like a photocell, it contains photosensitive material that gives of electrins when light energy strikes it (outside voltage is required)

Answer 20

phototube

Question 21

detects and amplifies radiant energy

Answer 21

photomultiplier (PM) tube

Question 22

in photomultiplier (PM) tube, when does electrons be transmitted?

Answer 22

when an incident light strikes the coated cathode

Question 23

in photomultiplier (PM) tube, what are the series of anodes that give off many secondary electrons when hit by single electrons (emitted electrons are attracted to this)

Answer 23

Dynodes

Question 24

the photomultiplier (PM) tube is how many times more sensitive than the phototube?

Answer 24

200x

Question 25

photodetector used in instruments design to to be extremely sensitive to very low light levels and light flashes of very short duration

Answer 25

photomultiplier (PM) tube

Question 26

photodetector where the absorption of radiant energy by a reversed-bias positive-negative (PN) junction diode prodices a photocurrent that is proportional to the incident radiant power

Answer 26

Photodiodes

Question 27

photodetector useful in application where light levels are adequate because if their excellent linerity an speed

Answer 27

Photodiodes