Elec Unit review

Question 1

Static electricity

Answer 1

the imbalance of electric charge at rest

Question 2

current electricity

Answer 2

the movement of charge or electrons

Question 3

Law of attraction and repulsion

Answer 3

• objects with same charges repel
• objects with opposite charges attract
• charged objects will sometimes attract neutral objects

Question 4

uses for electrostatics in daily life

Answer 4

photocopier and spray paint

Question 5

friction

Answer 5

2 neutral objects of different materials are rubbed together, electrons transfer from 1 to the other ex: silk+ ebonite-

Question 6

conduction

Answer 6

a charged object touches a neutral object
electrons move to or from the charged object to try and become neutral again

Question 7

induction

Answer 7

bringing an object close to the neutral object

Question 8

grounding

Answer 8

removing charges from an object with a larger neutral object

Question 9

importance of grounding wire on equipment

Answer 9

it adds a path for electrons to flow out of the circuit so it doesn’t hurt people or damage the device

Question 10

electric discharge

Answer 10

occurs when excess electrons are rapidly transferred

Question 11

how does a balloon stick on the wall

Answer 11

the negative charges are attracted to the positive charges on the wall

Question 12

lightning rod

Answer 12

protects the structure from lightning

Question 13

conductors

Answer 13

allows electrons to move through it easily ex: paperclip

Question 14

insulators

Answer 14

prevents the flow of electrons ex: eraser

Question 15

4 parts of a Circuit

Answer 15

conducting wire- allows electrons to flow
switch- controls circuit
load- uses the energy
source- provides energy

Question 16

series circuit

Answer 16

• electrons must pass through the load one after the other
  -has 1 path
  -if 1 goes out, they all do
• every lamp dims the light

Question 17

parallel circuit

Answer 17

• each load has separate supply of electrons
• 2 or more paths
• if 1 goes out, it doesn’t affect the other
  -every lamp added doesn’t affect the others

Question 18

why parallel circuit is best for the kitchen

Answer 18

allows other appliances to work if others are turned off

Question 19

4 things that affect resistance

Answer 19

material- copper=Low R nichrome= high R
length- longer wire= high R
thickness- thicker wire= Low R
Temp- High temp= High R

Question 20

Ohms law equation

Answer 20

R=V/I I=V/R V=IxR

Question 21

renewable resource

Answer 21

natural source that is unlimited

Question 22

non-renewable

Answer 22

resource that cant be replaced

Question 23

off peak hrs electricity usage

Answer 23

7am-7pm Mon-Fri

Question 24

% efficiency calc

Answer 24

Eout/Einx100

Question 25

cost of elec calc

Answer 25

cost to operate= power used x time x cost of elec