Science chpt 5

Question 1

What is electricity by définition??

Answer 1

-describes all phenomenon caused by positive and negative charges

Question 2

What are the charges of each particle??

Answer 2

-protons: positive
-neutrons: neutral
Electrons: negative

Question 3

Do like charges propel or attract?

Answer 3

-propel

Question 4

Do unlike charges propel or attract?

Answer 4

-attract

Question 5

What is the law of conservation of charges?

Answer 5

-electric charges can neither be created or destroyed only transformed from one body to another

Question 6

Why do most objects carry the same amount of protons and neutrons?

Answer 6

-they are electrically neutral

Question 7

What is a conductor by definition??

Answer 7

-a material that allows the free flow of electrical charges

Question 8

What are example of conductors?

Answer 8

-metals, electrolytic solutions

Question 9

What is an insulator by definition?

Answer 9

-a material that stops or impedes the flow of electrical charges

Question 10

What are example of insulators??

Answer 10

-wood, plastic, rubber

Question 11

What is a semi-conductor by definition??

Answer 11

-an thing that has variable conductivity depending on various factors

Question 12

What is static electricity by definition?

Answer 12

-describes all the phenomenon related to electrical charges at rest
-electrically charged things do not remain charged

Question 13

What is electrostatic charges?

Answer 13

-when two objects of opposite charge touch each other there is a release of charge

Question 14

What are the three main ways to charge an object??

Answer 14

1)friction charge
2) conduction
3) induction

Question 15

What is charging by friction??

Answer 15

When two neutrally charged objects are rubbed against each other, sometimes in one of them may pull electrons from the other resulting in who objects with different charges

Question 16

What does the direction of electron transfer depend on??

Answer 16

• depends on the tendency of an object to gain or give up electrons
  -the placement on the triboelectric series

Question 17

What is charging by conduction??

Answer 17

-done by putting an object in contact with another object that is already charged
-result: who similarly charged objects (but one has a weaker charge

Question 18

What is charging by induction??

Answer 18

-happens without objects touching each other
-when an electrically charged object approaches a neutral object without touching it opposite charges accumulate on the side of the neutral object

Question 19

What is Dynamic electricity??

Answer 19

• when electrical charges are placed in a circuit flowing in a loop the flow is referred to as dynamic electricity

Question 20

What is current by definition??

Answer 20

-the orderly flow of negative charges carried by electrons
-order is negative —> positive

Question 21

What is current intensity?

Answer 21

-current intensity is the # of charges that flow in a given point in the electrical second every second

Question 22

What is the symbol and units of current intensity??

Answer 22

Units: amperes
Symbol: A

Question 23

How do measure current intensity with ampeter??

Answer 23

-placed in the path that the current flows

Question 24

What is potential different??

Answer 24

• the energy that can be supplied by each of the charges in an electrical current
  -amount of energy transferred between 2 points on a circuit

Question 25

What is the unit and symbol for voltage

Answer 25

Symbol: V Units: volts V

Question 26

What is the instrument used to measure potential difference??

Answer 26

- called a voltmeter it calculus the amount of energy each of the chargers transfers to a circuit element -placed at the points where the current enters and exits the element (power source)

Question 27

What is resistance??

Answer 27

-the ability of a material to hinder the flow of electric current, the higher the resistance the more energy it takes for it to flow

Question 28

What is a resistor?

Answer 28

- a part in an electrical circuit that transform electrical energy to another form of energy

Question 29

What are the units and symbol for resistance

Answer 29

- symbol: ♎️ ohms

Question 30

What are factors that can affect the resistance of a substance??

Answer 30

1) nature of the substance 2) length, the longer the element or wire the greater the resistance 3) diameter, smaller diameter resists current more 4) temperature warm element resist flow more

Question 31

What is ohm’s law??

Answer 31

V= R • I V=potential difference in volts R=resistance in ohms I=current intensity in amperes

Question 32

What is electrical power?

Answer 32

-the amount of work an electrical circuit can do in 1 second -the more powerful the device the faster it will work -the measure of the rate of transformation of electrical energy

Question 33

What are the units for electrical power??

Answer 33

Wats or kilowatts

Question 34

How can you find the amount of electrical energy used by a device?!

Answer 34

-multiplying the electricity with the amount of time it was used

Question 35

What is the formula for electrical energy?

Answer 35

-E= p🔼t E=energy used (joules or kilowatts hours kWh) P=power in watts (kw) Delta T = the time interval expressed

Question 36

When using the measurements in KWh what time does it have to be in?

Answer 36

-hours

Question 37

What must the circuit be if they want the current to flow?

Answer 37

-in a closed loop

Question 38

What do all electric circuits contain??

Answer 38

-a power supply (potential difference) -one more elements that use electrical energy such as lightbulb or element -wires to carry the charges to and form the power source

Question 39

What are the two types of circuits?

Answer 39

-series circuits -parallel circuit

Question 40

What is a series circuit??

Answer 40

- a circuit in heavy the elements are connected end to end (one after the other)

Question 41

What are characteristics of series circuits?

Answer 41

1) if one of the components is defective the entire circuit stop working since the charge can no longer flow threw it 2) the energy is used by the resistors adds so they each new resistor the amount of energy available is reduced

Question 42

How must fuses and breakers be placed in a circuit to be effective?

Answer 42

-must be connected in series so that the current will cut off in case of overload

Question 43

What is a parallel circuit??

Answer 43

-contains at least one branch -current flows in different paths -intersections are called nodes

Question 44

What are characteristics of parallel circuits?

Answer 44

1) if an element is defective the elements in the other branch can continue working 2) the effect of the resistors is shared among the various pathways the total resistance therefore are added up

Question 45

Since the current intensity is shared among the resistors what happens?

Answer 45

-the demand for current increases, as does the risk of overload -useful to instal protective devices