CH. 10 Electricity

Question 1

Change in potential energy caused by the flow of electrons from an area of high concentration to an area of low concentration is:

Answer 1

Electricity

Question 2

High charge density to low charge density is

Answer 2

electricity

Question 3

1 Coulomb =

Answer 3

1.6 ^19 electrons

Question 4

Coulomb’s Law =

Answer 4

Like charges repel, opposite charges attract.

Question 5

This represents electrical “pressure” or the gradient of charges that could potentially flow

Answer 5

Electrical potential (V)

Question 6

electrical potential (V) is measured in what units?

Answer 6

Volts

Question 7

Rate of flow of an electrical charge through a conductor

Answer 7

Current (I)

Question 8

Materials in which charges can easily move are called

Answer 8

conductors

Question 9

conductors have low resistance to

Answer 9

flow

Question 10

insulator have no electrons that are easily moved. therefore, they resist

Answer 10

flow of electricity

Question 11

Current is measured in:

Answer 11

amperes

Question 12

an ampere is the flow of:

Answer 12

1 coulomb per second

1A=1C/sec

Question 13

Ohm’s Law measures

Answer 13

resistance to electrical flow

Question 14

Ohm’s Law relates:

Answer 14

V (electrical potential)
I (Current)
R (resistance)

Question 15

Resistance is measured in

Answer 15

ohms

Question 16

the closed path through which a charge flows is:

Answer 16

electrical circuit

Question 17

An electrical circuit in which the current flows in one direction only is:

Answer 17

direct current (DC) circuit

Question 18

an electrical circuit in which the current reverses its direction in a periodic fashion at a set frequency, usually 60hz

Answer 18

Alternating current (AC) circuit

Question 19

A situation in a circuit where the normal resistance of the circuit is bypassed by a low resistance path resulting in a large current:

Answer 19

short circuit

Question 20

If the current from a short circuit is not limited by a fuse/ circuit breaker, the resulting heat from the high current can lead to

Answer 20

a fire

Question 21

When batteries or resistors are connected in a series, the voltages and resistances are

Answer 21

added

Question 22

When resistors ar connected in parallel, current flows through each resistor

Answer 22

independently of the other

Question 23

Electrical power is the product of

Answer 23

volts and amps

P = IV

Question 24

power is measured in

Answer 24

watts

1 watt = 1W = 1V*A

Question 25

A moderately good conductor of electricity is a

Answer 25

semiconductor

Question 26

ultrapure silicon is used to fabricate

Answer 26

semiconductors

Question 27

The precise electrical properties of the material (semiconductors) are controlled by

Answer 27

incorporating impurities or doping agents

Question 28

We live and work in a world of

Answer 28

energized circuits

Question 29

If you come into contact w/an external source of electricity, these are possible:

Answer 29

electrical shocks

Question 30

electrical shocks are also possible from

Answer 30

``` Stray capacitance (leaky) and inductance (transfer by electromagnetic waves) ```

Question 31

transfer by electromagnetic waves

Answer 31

inductance

Question 32

Stray capacitance

Answer 32

leaky

Question 33

Electrical shock can be divided into two categories:

Answer 33

1. macroshock | 2. microshock

Question 34

Large amts of current conducted through a pt's skin or other tissues. The extent of injury will depend on the amt of current and duration of exposure. These are:

Answer 34

macroshocks

Question 35

the delivery of small amts of current directly to the hear. very small currents (<= 50 micro amps) can produce V.fib. These are called:

Answer 35

microshocks

Question 36

Very high frequency current does not excited contractile tissue and does not cause

Answer 36

cardiac dysrhythmias

Question 37

the longer an individual is min contact with the electrical source:

Answer 37

the more dire the consequences - more energy released = more tissue damage - greater chance of v.fib

Question 38

Current can flow through your body if a part of your body completes a

Answer 38

circuit

Question 39

Three mechanisms of complete circuits:

Answer 39

1. direct wire contact w/ metal casing d/t insulation damage. this COMPLETES the electrical circuit. 2. inductance by electromagnetic field w/o physical contact 3. stray capacitance from the buildup of electrical potentials w/an AC current circuit.

Question 40

Polarized plugs - describe - benefits

Answer 40

- one narrow prong (high potential), one wide prong (low potential) - ensures plug is inserted in one orientation.

Question 41

3-pronged grounded plug - describe - benefits

Answer 41

- has a third, rounded prong to connect ground - third prong is wired directly to casing of electrical device. - should a high potential current come, it will go through 3rd prong instead of your body

Question 42

Ground fault circuit interrupter (GFCI)

Answer 42

circuits used near water source

Question 43

GFCIs immediately (w/in 1 ms) disrupt the flow of current in the circuit if a

Answer 43

change in the current is detected

Question 44

Modern OR pose serious potential risks to patients and staff d/t the presence of

Answer 44

- electrical devices - cords - puddles of conducting fluids

Question 45

to decrease the risk of electrical shock, electrical systems are isolated from the grounded supply through

Answer 45

Isolation transformers

Question 46

Isolation transformers rely on magnetic inductance to transfer a current from

Answer 46

the grounded electrical system to an ungrounded secondary system w/o the two sys physically contacting

Question 47

Ungrounded systems in the OR prevent

Answer 47

accidental shocks (resulting from simply touching a single live wire)

Question 48

Line Isolation monitor

Answer 48

device that alarms when a fault in an ungrounded system occurs

Question 49

Line isolation monitors are located b/w

Answer 49

live wires and a ground so that the impedance to current flow can be measured

Question 50

if contact is made b/w a live wire and a ground, current will flow resulting in an (from LIM):

Answer 50

alarm

Question 51

LIM alarm set point

Answer 51

b/w 2-5mA

Question 52

If the LIM alarm is triggered

Answer 52

determine if it is a true fault

Question 53

If the LIM gauge reads b/w 2-5mA =

Answer 53

there probably is too much electrical equipment plugged into the circuit

Question 54

if the LIM gauge reads >5mA =

Answer 54

likely a faulty piece of equipment is present in the OR

Question 55

if the LIM is triggered; faulty equipment may be identified by :

Answer 55

unplugging each piece of equipment until the alarm is silenced

Question 56

if faulty equipment is not essential, it should be

Answer 56

removed from the OR

Question 57

Disadvantage of using a GFCI in the OR?

Answer 57

it interrupts the power w/o warning

Question 58

Defective equipment can no longer be used. This might be a problem if it were necessary for

Answer 58

life support

Question 59

electrically susceptible patients (microshock)

Answer 59

- v.fib can be produced by a current that is below the threshold of human perception (1mA) - stray's may result in significant amts of charge build up

Question 60

the ground wire on a piece of equipment provides a low-resistance pathway for leakage current and constitutes the major source of

Answer 60

protection against microshock (in electrically susceptible patients)

Question 61

Never simultaneously touch an electrical device and a saline filled

Answer 61

Central venous catheter or external pacing wires (wear rubber gloves!)

Question 62

Patient monitors are designed to

Answer 62

electrically isolate all direct pt connections from teh power supply of the monitor

Question 63

Electrocautery devices use high frequency electrical current to

Answer 63

cauterize, cut, and destroy tissue

Question 64

bipolar devices do no require return electrode and are less likely to cause

Answer 64

burn or injury

Question 65

this type of electrocautery device requires return electrode:

Answer 65

unipolar

Question 66

electrocautery may interfere in

Answer 66

ecg | pacemaker