Intro to dental radiography

Question 1

what is a radiograph?

Answer 1

an image produced by xrays passing through an object and interacting with the photogenic emulsion on a film

Question 2

what is in the nucleus?

Answer 2

protons - positive

neutrons - neutral charge

Question 3

what surrounds the nucleus?

Answer 3

electrons - negative charge

orbit around nucleus in different energy shells

Question 4

what do electrons move in?

Answer 4

predetermined shells with different energy levels

Question 5

how many electrons do shells contain?

Answer 5

K=2, L=8, M=18, N=32, O=50

Question 6

can electrons move between shells?

Answer 6

can move from shell to shell but cannot exist between shells = forbidden zones

Question 7

how is an electron removed?

Answer 7

energy required to overcome the binding energy and remove the electon

Question 8

what is a radioisotope?

Answer 8

isotopes with unstable nuclei which undergo radioactive disintegration

Question 9

alpha particles?

Answer 9

2 protons and 2 neutrons
large and slow speed
positive
1-2mm tissue penetration
4-8MeV of energy
damage potential - extensive ionisation

Question 10

beta particles?

Answer 10

fast moving electrons, small with negative charge, fast spread, 1-2cm penetration, 100beV - 6MeV energy
damage potential - ionisation

Question 11

gamma rays?

Answer 11

electromagnetic radiation
no size/charge, fast speed
can pass through tissue
1.24keV - 12.4 MeV energy
damage potential - ionisation

Question 12

X rays used in dentistry?

Answer 12

do not occur naturally
not involved in radioactive decay
identical to gamma rays - not such high energy values
no charge/very fasat
cause ionisation

Question 13

Electromagnetic spectrum?

Answer 13

stream of photons that have no mass
travel at speed of light
photons have diff amounts of energy
energy affects their properties

Question 14

what is basis electricity?

Answer 14

current is passed along a wire by the vibration of electrons

passed from -ve to +ve