Electricity & Electrical Safety - Quiz 5 Flashcards Preview

Spring 2020 - Chemistry & Physics > Electricity & Electrical Safety - Quiz 5 > Flashcards

Flashcards in Electricity & Electrical Safety - Quiz 5 Deck (33)
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What are the Two Types of Electrical Charges

Positively Charged - More protons than electrons

Negatively Charged - Less protons than electrons


What is the Fundamental Principle of Charge Interaction?

Coulomb's Law

Opposite charges attract

Same charges repel


What is Electrical Current?

Amount of Charge flowing per unit time

1 ampere = 1 Coulomb charge per second


What are Electrical Conductors?

Materials where charges easily move

Atoms that dont hold on tightly to electrons

Outer shell mostly empty


What are Electrical Insulators?

Nonmetals that are not good conductors


What is the Molecular Orbital approach to bonding?

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


What is Electrical Resistance?

Energy needed to push electrons through a material

Resistance (R) measured in ohms (Ω)


Ohm's Law

Electrical Potential = Current x Resistance

V = IR


Conductance Formula

Reciprocal of Resistance measured in mhos or siemens

G = 1/R


What is an Electric Circuit?

The closed Path through which a charge flows


What is a Direct Current Circuit?

A circuit where the charge flows in one direction


What is an Alternating Current Circuit?

A circuit where the current reverses its direction periodically


What is a Short Circuit?

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


How is the Total Resistance found in a Series Circuit



How is the Total Resistance found in Parallel Circuits?

Inversely Additive

Current flows thru each resistor indepently of each other

1/Rtotal = 1/R1 + 1R2 + 1/R3...


What unit is Electrical Power measured?

Electrical Power = Volts x Amps

Measured in Watts

1 watt = 1 V x A


What is the difference between Power & Energy?

Power = Energy/Time

Energy = Power x Time
(We Pay For Energy)


What are the different types of Electrical Shocks?

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

Microshock - small amt. of current directly to the heart


How big of a microshock will cause Ventricular Fibrillation?

< 50 µA can cause V Fib


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

The Ground Wire

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


How do Patient Monitors protect the patient from Microshock?

Isolates all direct patient connections from the power supply


How are modern plugs made to be safer from Shock?

Polarized Plugs - one narrow and one wide prong

Wide Prong = Low Potential


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

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


What is the Ground Fault Circuit Interrupter (GFCI)?

Used in circuits near water.

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


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

Power can be stopped w/o warning

Defective Equipment can longer be used


How can Ground Systems still pose a risk?

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


How do Modern ORs decrease the risk of Electrical Shock?

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


How do Isolation Transformers work?

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


Do you want Grounded or Ungrounded systems in the OR?



What is considered an Electrical "Fault"?

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

A Second Fault can cause a Shock