Lesson 1 - SI Units

Question 1

Name the 3 components in an SI unit

Answer 1

Prefix
Unit symbol
Exponent

Question 2

What is a vector quantity

Answer 2

A quantity with direction and magnitude

Question 3

What is a scalar quantity

Answer 3

A quantity with only magnitude

Question 4

Define force

Answer 4

A movement from a stationary bidy that alters the speed or direction if a moving body

Question 5

Define work

Answer 5

Energy transferred when a force moves an object
Energy that is usefully sounded

Question 6

Define power

Answer 6

Rate of doing work or rate of using energy
Joules per second/ watts

Question 7

Define unit of work

Answer 7

Product of magnitude of the force and the distances moved in the direction of the force

Question 8

Why are SI units not always convenient

Answer 8

They may be too large or too small

Question 9

Derived quantities are produced from a combination of SI base units and always contain one of the following three base units:

Answer 9

m, kg, s

Question 10

how many measurements are in the SI system

Answer 10

7 base units

Question 11

what is equal to 1mSv

Answer 11

10-6 Sv

Question 12

what expresses a millionth

Answer 12

micro

Question 13

is atomic number oir mass bigger

Answer 13

mass. located at the topic with protons and neutrons

Question 14

What is the name of the band of electron orbitals that electrons can jump up into from the valence band via a process called excitation?

Answer 14

conduction band

Question 15

Which is a form of electromagnetic ionising radiation?

Answer 15

gamma decay

Question 16

What type of ionising radiation are X-rays?

Answer 16

electromagnetic

Question 17

Of what element is the rotating anode disc made?

Answer 17

tungsten

Question 18

list required characteristics of the filament in an X-Ray machine

Answer 18

-strong metal
low vapour pressure
-low thermionic work function

Question 19

A continuous X-Ray spectrum is produced by which interactions?

Answer 19

An X-ray photon being absorbed by an electron in an atom is called photoelectric absorption.

An X-ray photon being scattered by an electron in an atom is called Compton scatter.

Question 20

define attenuation

Answer 20

reduction in energy per unit area of x-ray beam

Question 21

what has no affect on attenuation

Answer 21

collimation

Question 22

what is the half value thickness

Answer 22

The thickness of a substance that will transmit 50% of the x-ray photons to which it is exposed

Question 23

in compton interaction, where can a phoyon be scattered

Answer 23

in any direction

forward
backwards
sideways

Question 24

What does ‘0.25mm lead equivalent’ mean?

Answer 24

A material attenuates the x-ray beam as much as 0.25mm of lead

Question 25

What does ‘mAs’ indicate?

Answer 25

Tube charge