Electricity & Magnetism (E1)

Question 1

Electric charge

Answer 1

Positive or negative
Like charges repel and opposites attract

Question 2

Electrical potential

Answer 2

A particle with a charge generates an electrical field around it

Question 3

Electric current

Answer 3

-moving electric charge due to moving electrons
-flows in opposite direction of flowing electrons
-measured in amperes
-flows from a place of high electrical field to lower electrical field

Question 4

Insulator

Answer 4

A substance that will not allow a current to flow through it
Ex. Plastic, rubber, glass

Question 5

Conductor

Answer 5

Substance that will conduct an electric current
Ex. Metals, electrolyte solutions

Question 6

Basic electrical circuit

Answer 6

1. Electrical potential source (battery)
2. Something to carry the current (wire)
3. Something resists the flow of current (light bulb)

Question 7

Ohm’s Law

Answer 7

Current = voltage difference / resistance

Question 8

Direct current (DC)

Answer 8

Current flows in one direction

Question 9

Alternating current (AC)

Answer 9

Current oscillates
-induces magnetic fields

Question 10

Magnetism

Answer 10

-always has North and south poles
-tesla or gauss

Question 11

Ferromagnet

Answer 11

Substance with unpaired electron where atoms are PERMANENTLY aligned to sum their magnetic field
-one side always North and one side always South

Question 12

Paramagnet

Answer 12

No magnetic properties without a field nearby
-unpaired electrons align opposite the field so the substance is always ATTRACTED

Question 13

Diamagnet

Answer 13

No magnetic properties without a field nearby
-unpaired electrons align in same direction as the field so the substance is always REPELLED

Question 14

Electromagnet

Answer 14

Physically moving charge creates a magnetic field
-straight wire: magnetic field wraps around the wire
-coiled wire: circular pattern creating donut shape

Question 15

Electromagnetic induction

Answer 15

Process where a changing magnetic field induces an electric field

Question 16

Transformers

Answer 16

-consist of 2 isolated loops of wire
-AC current in first wire creates changing magnetic field in first set of wire loops that are felt by second set of wire loops and generates a changing AC currebt

Question 17

Ways to prevent shock

Answer 17

1. Insulation
2. Ground the casing (3rd prong)
3. Use a ground fault interruptor (GFCI)
4. Use an isolation transformer (OR)

Question 18

Line isolation monitor

Answer 18

-no grounding, no flow through LIM
-grounding = current through LIM (leakage current)
-alarms if current is 2-5 mA
-protects against macroshock

Question 19

Macroshock

Answer 19

-shock delivered through skin
-needs large current to overcome resistance
100 mA = vfib

Question 20

Microshock

Answer 20

-shock delivered to body but bypasses the skin
-injury can occur with lower currents
-100 uA = vfib

Question 21

Monopolar cautery

Answer 21

-single tip
-requires grounding pad with full contact and not over metal

Question 22

Bipolar cautery

Answer 22

-two tips
-no grounding pad
-vetter for pacemakers