Unit 4 Review

Question 1

Power Formula

Answer 1

P=IV

Question 2

Power Loss

Answer 2

Ploss=(I^2) R

Question 3

Ohms Law

Answer 3

V=IR

Question 4

Example of a natural magnet

Answer 4

Earth

Question 5

Ferromagnetic Define and Example

Answer 5

Highly permeable, strong attraction, easily magnetized

Ex: ordinary magnets

Question 6

Paramagnetic

Answer 6

weak attraction to magnets

Ex: Aluminum

Question 7

Diagmagnetic

Answer 7

Repelled by magnets

Ex: Lead, berillium, water

Question 8

Non magnetic

Answer 8

no attraction to magnet/insulator

Ex: Plastic/rubber

Question 9

3 Laws of Magnetisim

Answer 9

1. all magnets have 2 poles, North and South
2. like poles repel, unlike poles attract
3. The forces of either attraction or repulsion are directly proportional to the strength of poles and inversely proportional to the distance between them

Question 10

What happens if you break a magnet

Answer 10

The original north and south poles remain, new north and south poles opposite from the side of the break occur where the break happened

Question 11

Once magnetized, do all elements remain permanently magnetized

Answer 11

no

Question 12

What are the directions of the flux lines inside and outside magnets

Answer 12

Internal: South to North
External: North to South

Question 13

Define EM induction

Answer 13

Generating eletrical current using a magnetic field

Question 14

Define mutual induction

Answer 14

AC through primary coil creates a fluxuation magnetic field and that induces AC into 2ndary coil

Question 15

What item in xray circuitry operates on mutual induction principle

Answer 15

Step up and step down transformers

Question 16

Define Self Induction

Answer 16

Auto transformer-AC opposition of currents own flow because current reverses itself

Question 17

Define permeability

Answer 17

Ease which a material is magnetized

Question 18

Define retentivity

Answer 18

The ability of material to resist demagnetization

Question 19

What kind of retentivity do we prefer for xray

Answer 19

low, we want the magnetism to decrease fast after exposure

Question 20

Define magnetic dipoles/domains

Answer 20

Atoms with their magnetic field spinning the same direction

Question 21

Helix

Answer 21

coil of wire

Question 22

Solenoid

Answer 22

helix attatched to source of energy

Question 23

Electromagnet

Answer 23

A solenoid with a ferromagnetic core

Question 24

Where do we find solenoids and electromagnets used in an xray circuit

Answer 24

Transformers
Bucky lock
Tube detents

Question 25

Faradays ways of using a magnet to create an electric current

Answer 25

1. Move conductor in relationship to stationary magnetic field.
2. Move magnetic field in relation to a stationary conductor
3. Vary the strength of magnetic field with no moving parts

Question 26

What happens to voltage in step up

Answer 26

increases

Question 27

What happens to voltage in step down

Answer 27

decreases

Question 28

Describe step up and step down transformers physically, which side has more turns

Answer 28

Step up: Rt has more turns

Step down: Lt has more turns

Question 29

Primary side is always connected to what and secondary side is always connected to what

Answer 29

Primary connected to the source of power

Second attached to load

Question 30

Transformers operate and produce what type of current

Answer 30

AC

Question 31

Why do we use transformers in xray

Answer 31

Create high enough voltage to make xrays