Electricity & Electrical Safety - Quiz 5

Question 1

What are the Two Types of Electrical Charges

Answer 1

Positively Charged - More protons than electrons

Negatively Charged - Less protons than electrons

Question 2

What is the Fundamental Principle of Charge Interaction?

Answer 2

Coulomb’s Law

Opposite charges attract

Same charges repel

Question 3

What is Electrical Current?

Answer 3

Amount of Charge flowing per unit time

1 ampere = 1 Coulomb charge per second

Question 4

What are Electrical Conductors?

Answer 4

Materials where charges easily move

Atoms that dont hold on tightly to electrons

Outer shell mostly empty

Question 5

What are Electrical Insulators?

Answer 5

Nonmetals that are not good conductors

Question 6

What is the Molecular Orbital approach to bonding?

Answer 6

Individual Atomic Orbitals are added together to form a molecular orbital extending over the entire molecule

Question 7

What is Electrical Resistance?

Answer 7

Energy needed to push electrons through a material

Resistance (R) measured in ohms (Ω)

Question 8

Ohm’s Law

Answer 8

Electrical Potential = Current x Resistance

V = IR

Question 9

Conductance Formula

Answer 9

Reciprocal of Resistance measured in mhos or siemens

G = 1/R

Question 10

What is an Electric Circuit?

Answer 10

The closed Path through which a charge flows

Question 11

What is a Direct Current Circuit?

Answer 11

A circuit where the charge flows in one direction

Question 12

What is an Alternating Current Circuit?

Answer 12

A circuit where the current reverses its direction periodically

Question 13

What is a Short Circuit?

Answer 13

When the normal resistance in a circuit is bypassed by a low resistance path resulting in a Large Current

If there is no fuse or circuit breaker = Fire

Question 14

How is the Total Resistance found in a Series Circuit

Answer 14

Additive

Question 15

How is the Total Resistance found in Parallel Circuits?

Answer 15

Inversely Additive

Current flows thru each resistor indepently of each other

1/R_total = 1/R₁ + 1R₂ + 1/R₃…

Question 16

What unit is Electrical Power measured?

Answer 16

Electrical Power = Volts x Amps

Measured in Watts

1 watt = 1 V x A

Question 17

What is the difference between Power & Energy?

Answer 17

Power = Energy/Time

Energy = Power x Time
(We Pay For Energy)

Question 18

What are the different types of Electrical Shocks?

Answer 18

Macroshock - large amt. of current conductred thru pts skin or other tissues

Microshock - small amt. of current directly to the heart.

Question 19

How big of a microshock will cause Ventricular Fibrillation?

Answer 19

< 50 µA can cause V Fib

Question 20

What provides a low-resistance pathway for current leakage and is the major source of protection against microshock?

Answer 20

The Ground Wire

Never touch an electric device & a saline-filled CVP catheter or pacing wire at the same time

Question 21

How do Patient Monitors protect the patient from Microshock?

Answer 21

Isolates all direct patient connections from the power supply

Question 22

How are modern plugs made to be safer from Shock?

Answer 22

Polarized Plugs - one narrow and one wide prong

Wide Prong = Low Potential

Question 23

What is the Third Prong of a Plug and how does it work?

Answer 23

The Ground Prong - Wired directly to the casing of electrical device

Question 24

What is the Ground Fault Circuit Interrupter (GFCI)?

Answer 24

Used in circuits near water.

Immediately disrupts flow of current if a change in current is detected

Question 25

What is a disadvantage of using a Ground Fault Circuit Interrupter (GFCI) in an OR?

Answer 25

Power can be stopped w/o warning

Defective Equipment can longer be used

Question 26

How can Ground Systems still pose a risk?

Answer 26

People who are at Ground Potential just need to touch a single object to complete a circuit shock

Question 27

How do Modern ORs decrease the risk of Electrical Shock?

Answer 27

Electric Systems are isolated from the Grounded Electrical Supply through Isolation Transformers

Question 28

How do Isolation Transformers work?

Answer 28

Rely on Magnetic Inductance to transfer current b/t grounded & ungrounded systems without the two actually touching

Question 29

Do you want Grounded or Ungrounded systems in the OR?

Answer 29

Ungrounded

Question 30

What is considered an Electrical “Fault”?

Answer 30

When a Live wire touches the ground or equipment casing causing the ungrounded system to become grounded

A Second Fault can cause a Shock

Question 31

What is a Line Isolation Monitor?

Answer 31

Device that alarms when a fault occurs

Located b/t live wires & ground

Alarm set at 2-5 mA

Does NOT provided protection from shock

Question 32

What should be done if the Line Isolation Monitor alarms?

Answer 32

• If 2 - 5 mA: too many things plugged in
• If > 5 mA: Faulty piece of equipment
• Unplug each thing until alarm stops and remove from OR

Question 33

How does Electrosurgery Work?

Answer 33

High-Frequency currents generates heat

High frequency currents have low tissue penetration to contractile cells

Must make sure return plate is applied properly!

Power supply is isolated from the ground