electricity

Question 1

what is electricity

Answer 1

the effects produced by moving charges

Question 2

SI unit of charge is the

Answer 2

coulomb (C)

Question 3

positively charged contains ___ protons than electrons

Answer 3

more

Question 4

negatively charged contains ___ protons than electrons

Answer 4

less

Question 5

fundamental principle of charge interaction

Answer 5

positively charged object will attract a negatively charged object

Question 6

Coulomb’s law

Answer 6

the magnitude of the electrostatic force of attraction or repulsion

Question 7

a current going down a line is __ energy

Answer 7

kinetic

Question 8

electrical current is defined as

Answer 8

the amount of charge flowing per unit time

Question 9

materials in which charges can easily move

Answer 9

conductor

Question 10

an amp of current corresponds to

Answer 10

1 coulomb of charge per second

Question 11

to be a good conductor,

Answer 11

electrons must be able to move easily from one atom to the next

Question 12

most insulators are ___ and generally not good conductors except for

Answer 12

graphite

Question 13

the energy required to push electrons though a material is a measure of the

Answer 13

resistance

Question 14

resistance is measured in

Answer 14

ohms

Question 15

ohm’s law relates

Answer 15

electrical potential = impedance x resistance

Question 16

the reciprocal of resistance is

Answer 16

conductance

Question 17

conductance is measured in

Answer 17

mhos

Question 18

electric circuit

Answer 18

the closed path through which a charge flows

Question 19

direct current (DC) circuit

Answer 19

an electrical circuit in which the current flows in one direction only

Question 20

alternating current (AC) circuit

Answer 20

an electrical circuit in which the current reverse its direction in a periodic fashion

Question 21

short circuit

Answer 21

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

Question 22

series circuits - when batteries or resistors are connected in a series, the voltages and resistances are

Answer 22

added

Question 23

when resistors are connected in parallel,

Answer 23

current flows through each resistor independently of the other

Question 24

power =

Answer 24

the rate of using energy. energy/time.

Question 25

diodes

Answer 25

Diodes are circuit elements that have large conductance’s in one direction and a smaller in reverse. Used to control the current direction. Effective diodes can be made having p-type nad n-type regions next to each other.

Question 26

forward bias (?)

Answer 26

n region negative, p region positive... slide 31

Question 27

reverse bias (?)

Answer 27

has depletion region and high resistance

Question 28

transistor

Answer 28

used to amplify or switch currents

Question 29

macroshock

Answer 29

large amt of current conducted thru a patients skin or other tissues. the extent of injury will depend on the amt of current and the duration of the exposure

Question 30

microshock

Answer 30

the delivery of small amt of current directly to the heart.

Question 31

microshock is a risk for

Answer 31

v-fib (<50 uA)

Question 32

v-fib can be produced by a current that is below the threshold of human perception

Answer 32

1 mA

Question 33

polarized plug

Answer 33

one narrow(high potential) one wide prong (low potential) so they can only go in the wall the correct way.

Question 34

three-pronged grounded plug

Answer 34

some electrical devices have a rounded third prong that is connected to ground when plugged into a three-pronged receptacle. This third prong is wired directly to the casing of the electrical device. if for some reason a high-potential wire comes into contact with the case, the current will flow directly though the third prong instead of through your body.

Question 35

ground fault circuit interrupter

Answer 35

used in circuits near water sources. GFCIs immediately (within 1ms) disrupt the flow of current in the circuit if a change in current is detected.

Question 36

disadvantage of GFCI

Answer 36

interrupts the power without warning - the defective piece of equipment can no longer be used, which might be a problem if it were necessary for life support

Question 37

ground systems - risk to humans

Answer 37

humans who are at ground potential because of what they are touching have to only touch a single object to complete a circuit, resulting in shock.

Question 38

to further decrease the risk of of electrical shock, electrical systems are ___ from the grounded electrical supply through the use of isolation transformers

Answer 38

isolated

Question 39

isolation transformers

Answer 39

rely on magnetic inductance to transfer a current from the grounded electrical system to an ungrounded secondary system without the two systems physically contacting each other.

Question 40

line isolation monitor

Answer 40

Alarms when a fault in an ungrounded system occurs- piece of equipment is causing a ground. a second fault can result in a shock

Question 41

line insolation monitors are located

Answer 41

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

Question 42

alarm set point for line isolation monitor is between

Answer 42

2-5

Question 43

which two factors determine installing an isolated power

Answer 43

is the operating room a wet location? and if so is an interruptible power supply acceptable?

Question 44

___ is used to convert grounded power to ungrounded power

Answer 44

isolation transformer

Question 45

_____ warns that isolation of the power from ground has been lost in the event that a defective piece of equipment has been plugged into one of the isolated circuit outlets

Answer 45

line isolation monitor