Physics Test Review

Question 1

electrically neutral

Answer 1

describes an object that has equal amounts of positive and negative charges

Question 2

charging by friction

Answer 2

process of charging materials by rubbing them together

Question 3

insulator

Answer 3

A material in which electrical charges cannot move easily. (ex. glass, wood, styrofoam, plastic)

Question 4

conductor

Answer 4

a material in which electrical charges can move easily (ex. copper, iron, gold, silver)

Question 5

how to test whether something is a conductor or insulator

Answer 5

conductivity meter. if material is insulator, no movement or light, if material is conductor, light or action

Question 6

static electricity

Answer 6

the buildup of negative charges in one place

Question 7

law of electric charge

Answer 7

opposites attract, likes repel

Question 8

electroscopes

Answer 8

used to detect electric charge (ex. Pith Ball, Metal Leaf)

Question 9

charging by conduction (contact)

Answer 9

Two differently charged objects come in contact
Electrons flow from the more negative object to the more positive
Objects will not necessarily be neutral but have the same amount of electrons afterwards

Question 10

charging by conduction: using a negatively charged object

Answer 10

Before contact, ebonite rod was negative and electroscope was neutral. You can tell as the leaves hung down. After contact, electrons from ebonite rod moved into electroscope making it negative. The leaves repel because they’re both positive

Question 11

what happens when we rub a charged object on a metal conductor?

Answer 11

metals allow electrons to move around freely, causing them to be unable to build up in one place or cause static electricity

Question 12

pith ball

Answer 12

-plant material hanging from string
-if a charged object is brough near it will move

Question 13

grounding

Answer 13

-way of removing excess charge
-transfer electrons from small object into large object such as the earth
-earth is large so it spreads out and becomes neutralized
-for a positive object electrons travel back into object until neutralized

Question 14

electric discharge

Answer 14

-quick transfer of electrons from one place to another
-happens when 2 objects with charge imbalances are brought together but do not touch
-electrons move from more negative to more positive

Question 15

what do we experience from electrical discharge

Answer 15

-crack or pop
-air temp increase
-sparks between objects

Question 16

lighting

Answer 16

-caused between ground and clouds
-electrons transferred between water droplets moving past each other. ex of charging by friction
-negative molecules collect at cloud bottoms

Question 17

lightning rod

Answer 17

-gives electrons safe path to the ground
-made of metal
-protects buildings

Question 18

current electricity

Answer 18

• refers to electrons that flow through a conductor in a controlled way, steady flow
• there is a steady flow of electrons through a conductor

Question 19

types of batteries (electrical cells)

Answer 19

• primary cells: single use batteries (lithium, alkaline)
• secondary cells: can be recharged by reversing the flow of electrons (lead-acid, NiMH, lithium)
• fuel cells: chemicals are continuously pumped into the cell, resulting in a longer battery life (hydrogen)

Question 20

types of current electricity

Answer 20

• direct: can only flow in one direction (ex. devices that use a battery)
• alternating: can flow in multiple directions (ex. generating stations flow in an alternating current)

Question 21

what is needed for electrons to flow in a current?

Answer 21

conductors because they hold electrons loosely

Question 22

what makes electrons flow through a conductor?

Answer 22

batteries

Question 23

where do applinces without batteries get electrons from?

Answer 23

outlets which are connected to power generating stations

Question 24

what are electrical charge measure in?

Answer 24

joules

Question 25

circuit

Answer 25

continuous loop consisting of an energy source, conducting wires, one or more loads, and a switch

Question 26

basic circuit requirements

Answer 26

a load, source of electricity, electrical conductor, and control device

Question 27

what type of electric cell is suitable for a flashlight or smoke detector?

Answer 27

primary cells as they have a low discharge rate than other types of batteries which is suitable for appliances like flashlights and smoke detectors as they are not often used
they are also quite compact and energy dense

Question 28

current

Answer 28

flow of charge (amount of charge passing through a point per second)

Question 29

what is current measured with? and whats the symbols

Answer 29

ammeter A and I

Question 30

potential difference

Answer 30

difference in potential energy per coulomb of charge at one circuit point compared to another

Question 31

what is potential difference measured with

Answer 31

voltmeter

Question 32

resistance

Answer 32

something that slows the flow of electrons in a circuit (the loads)
result of the conversion of energy to other forms as the current passes through a load

Question 33

what is resistance measured with?

Answer 33

ohmeter

Question 34

give 5 examples of current electricity generators

Answer 34

hydro-electric, biomass, geo-thermal, tidal, nuclear, solar, wind