# Unit 4 Review Flashcards

1
Q

Power Formula

A

P=IV

2
Q

Power Loss

A

Ploss=(I^2) R

3
Q

Ohms Law

A

V=IR

4
Q

Example of a natural magnet

A

Earth

5
Q

Ferromagnetic Define and Example

A

Highly permeable, strong attraction, easily magnetized

Ex: ordinary magnets

6
Q

Paramagnetic

A

weak attraction to magnets

Ex: Aluminum

7
Q

Diagmagnetic

A

Repelled by magnets

Ex: Lead, berillium, water

8
Q

Non magnetic

A

no attraction to magnet/insulator

Ex: Plastic/rubber

9
Q

3 Laws of Magnetisim

A
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
10
Q

What happens if you break a magnet

A

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

11
Q

Once magnetized, do all elements remain permanently magnetized

A

no

12
Q

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

A

Internal: South to North
External: North to South

13
Q

Define EM induction

A

Generating eletrical current using a magnetic field

14
Q

Define mutual induction

A

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

15
Q

What item in xray circuitry operates on mutual induction principle

A

Step up and step down transformers

16
Q

Define Self Induction

A

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

17
Q

Define permeability

A

Ease which a material is magnetized

18
Q

Define retentivity

A

The ability of material to resist demagnetization

19
Q

What kind of retentivity do we prefer for xray

A

low, we want the magnetism to decrease fast after exposure

20
Q

Define magnetic dipoles/domains

A

Atoms with their magnetic field spinning the same direction

21
Q

Helix

A

coil of wire

22
Q

Solenoid

A

helix attatched to source of energy

23
Q

Electromagnet

A

A solenoid with a ferromagnetic core

24
Q

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

A

Transformers
Bucky lock
Tube detents

25
Q

Faradays ways of using a magnet to create an electric current

A
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
26
Q

What happens to voltage in step up

A

increases

27
Q

What happens to voltage in step down

A

decreases

28
Q

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

A

Step up: Rt has more turns

Step down: Lt has more turns

29
Q

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

A

Primary connected to the source of power

Second attached to load

30
Q

Transformers operate and produce what type of current

A

AC

31
Q

Why do we use transformers in xray

A

Create high enough voltage to make xrays