Physics Lesson 4

Front 1

explain the difference between AC and DC

Back 1

AC is alternating current; back and forth flow of charge while DC is direct current; flow of charge in one direction

Front 2

What is a diode?

Back 2

a tiny electronic device that acts as a one-way valve to allow electron flow in only one direction

Front 3

what is a capacitor

Back 3

a capacitor is a device that can store electric energy

Front 4

what is voltage

Back 4

voltage is electrical ptential energy per charge

Front 5

define power

Back 5

power is the amount of work done in a given unit of time.

Front 6

what is the unit for power

Back 6

watt (w)

Front 7

does a thin wire or a thick wire have more resistance to the flow of curent?

Back 7

thin wires

Front 8

most electrical plugs have three prongs. what is the purpose of the third one?

Back 8

the third prong connects the body of the appliance directly to the ground. Any charge that builds up on an appliance is therefore conducted to the ground.

Front 9

Name one source each for DC and AC

Back 9

A battery for DC, Electric current provided to homes by large generators for AC

Front 10

What is the difference between a series circuit and a parallel circuit?

Back 10

a series circuit has the electrical current in one single pathway through the circuit. a parallel circuit has each electrical appliiance connected seperately to the battery so that a break does not interrupt the flow of charge in other paths.

Front 11

If one bulb goes out in a string of christmas lights connected in a series, will the rest of the bulbs remain lit

Back 11

no

Front 12

which circuit would have more total resistance, four lamps connected in series or four lamps connected in parallel

Back 12

four lamps connected in series

Front 13

what is a short circuit

Back 13

a low resistance connectionestablished by accident or intention between two points in an electric circuit. the current tends to flow through the area of low resistance, by passing the rest of the circuit.

Front 14

what is the purpose of fuses and circuit breakers?

Back 14

to protect electrical lines all the way back to the generators

Front 15

in order for current to flow in a circuit, should the switch be open or closed?

Back 15

closed

Front 16

what types of objects will a magnet attract?

Back 16

ones containing iron, nickel, cobalt, and aluminum in them

Front 17

how could you make an iron nail into a magnet?

Back 17

by attaching or stroking the nail with a magnet

Front 18

how does the earth's magnetic field protect it?

Back 18

it repels particles in space that try to enter earth.

Front 19

what is a galvonometer?

Back 19

a sensitive current indicating instrument that can be calibrated to measure current or electrical potential

Front 20

what is a motor?

Back 20

a device that converts electrical energy into mechanical energy.

Front 21

what is a generator?

Back 21

a device that converts mechanical energy into electrical energy.

Front 22

how was the relationship between eletricity and magnetism discovered?

Back 22

the relationship was discovered when Hans Christian Oersted was demonstrating electrical currents in front of a class.when electric current was passed in a wire near a magnetic compas both Oersted and his students noticed the deflection of the compass needle.

Front 23

what is a quantum

Back 23

a fixed amount of something

Front 24

what is a photon

Back 24

quanta of light energy.

Front 25

would a photon of red light have enough energy to eject an electron?

Back 25

no

Front 26

Explain the photoelectric effect

Back 26

the ejection of electrons from certain metals when light falls on them. only high frequency photons have enough concentrated energy to do this.

Front 27

what is chaos? give two examples.

Back 27

unpredictability and disorder in systems. Turbulent water flow, we cannot predict where a piece of wood will end up further downstram. Weather, we cannot predict accurately how a small change in one day's weather can produce big changes a week later.

Front 28

List three ways the photoelecric effect is used every day.

Back 28

in electric eyes, photographer's ligth meter, and in picking up sound from the sound tracks of motion pictures.

Front 29

who recieved the nobel prize for his explanation of the photoelectric effect?

Back 29

Albert Einstein

Front 30

Which would have enough energy to eject an electron, a blue photon or a red photon?

Back 30

blue photon

Front 31

how does an objct become negatively charged?

Back 31

by gaining one or more extra electrons than protons

Front 32

what materials make good conductors of electricity?

Back 32

metals

Front 33

Give two examples of good electric insulators

Back 33

rubber and glass

Front 34

what is a semiconductor and where are tehy commonly used?

Back 34

materials such as germanium and silicon that have at least one atom replaced with an impurity that adds or removes an electron form the crystal structure. they are commonly used in electrical transistors.

Front 35

what are 3 methods of charging an object

Back 35

friction, conduction and induction

Front 36

what would make a material a good electric insulator?

Back 36

materials in which electrons are tightly bound

Front 37

what is the SI unit for charge?

Back 37

coulomb

Front 38

what is lightning

Back 38

electrical discharge between oppositely charged parts of clouds or cloud (-) to ground (+)

Front 39

electric potential is commonly called

Back 39

voltage

Front 40

what is a capacitor? give three examples of how capacitors are used in our everyday lives

Back 40

capacitors are common devices found in nearly all electrical circuits. they are used to store energy.
1. power supply for TV's
2. used to store the 1's and 0's of the binary code in computer keyboards
3. Used to store mass amounts of energy that power giant lasers

Front 41

if a positive charge is placed in a positive electric field, will the charge move toward or away from the center of the field?

Back 41

it will move away from the center of the field