10 Science

Question 1

Is the push and pull of an object in a particular direction

Answer 1

Force

Question 2

Is an object that is made of materials that create a magnetic field

Answer 2

Magnets

Question 3

External force given of by a magnet and a area in which a magnet force can be felt

Answer 3

Magnet fields

Question 4

External force given of by a magnet and a area in which a magnet force can be felt

Answer 4

Magnet fields

Question 5

Is the property and interraction of magnets

Answer 5

Magnetism

Question 6

2 types of magnets

Answer 6

Natural and artificial

Question 7

Stone which possess the property to attract other stones are called load stone

Answer 7

Natural magnets

Question 8

Do not need matter to transfer energry

Answer 8

Electromagnetic waves

Question 9

Are made by vibrating electric charges and can travel through space by transfering enery between vibrating electric and magnetic fields

Answer 9

Electromagnetic waves

Question 10

How does moving charges create magnetic fields

Answer 10

Any moving electric charges is surrounded by an electric field and magnetic field

Question 11

Making of Electromagnetic waves

Answer 11

When an electric charge vibrate, the electric fields around it changes creating a changing magnetic fields

The magnetic and electric fields create each other again and again

An EM wave travels in all direction. The figure only shows a wave travelling in one direction.

Electric and magnetic fields vibrate at right angles to the direction the wave travels so it is a transverves wave

Question 12

Properties of EM Waves

Answer 12

All matter contains charged particles that are always moving,. Therefore all objects emit EM waves

The wavelenghts become shorter as the temperature of the material increases

EM waves carry radiant energy

Question 13

What is the speed of EM waves

Answer 13

300000 km/sec in space or vacuum
(speed of light natures limit

EM waves usually travel slowest in solid and fastest in gases

Question 14

Speed of EM wave
Vacuum=?

Answer 14

300,000 km/sec

Question 15

Speed of EM waves
Air=??

Answer 15

<300,000km/sec

Question 16

Speed of EM wave
Water=?

Answer 16

226,000km/sec

Question 17

Speed of EM wave
Glass=?

Answer 17

200,000km/sec

Question 18

Speed of EM wave
Diamond=?

Answer 18

124,000km/sec

Question 19

What is the wavelenght and frequency of an EM wave?

Answer 19

Wavelenght = distance from crest to crests
Frequency=number of wavelength that pass a given point in 1 sec.

As frequency increase wavelenght becomes smaller

Question 20

How does a radio receives different stations?

Answer 20

The modified carrier wave vibrates electrons in the stations antennae creating a radio wave that travels out in all directions at the speed of light to your radio antennae

The vibrating electrons produce a changing electric current which your radio seperates the carrier wave from the signal to make the speaker vibrate creating sound waves

Question 21

What is an AM radio?

Answer 21

In Am amplitude changes but frequency does not. AM frequency range from 540,000 Hz to 1,6000,000 Hz usually listed in kHz

Question 22

What is an FM radio

Answer 22

In FM radio station transmit broadcast information by changing the frequency of the carrier wave. The strength of FM waves is always the same and is in megahertz
Mega=million

Question 23

Uses radio waves to send electronic signals in a carier waves

Sound is sent by FM; color and brightness is sent at the same time by AM signals

Answer 23

Television

Question 24

Sound waves - microphone - electrical signals - radio waves - transmitted to and from microwave tower - receiver - electrical signal - speaker - sound wave

Answer 24

Telephones

Question 25

How do cordless phones work?

Answer 25

Cell phones and cordless telephones transceivers devices that transmits one signal and receives another radio signals from a base unit You can talk and listen at the same time because the two signals are the different frequencies

Question 26

A ____ is a small radio receiver with a phone number. A caller leaves a message at a terminal with a callback number At the terminal the message is turned into an electronic signal transmitted by radio waves Newer ____ can send and receive mesages

Answer 26

Pagers

Question 27

Thousand if satellites orbit Earth. A radio or TV station sends microwave signals to the satellite which amplifies the signal and sends it back to a different place on Earth. Satellite uses different frequency to send and receive.

Answer 27

Communication Satellites

Question 28

_______ is a system of 24 satellites, ground monitoring stations and portable receivers that determine your exact location on Earth. ______ receiver measures the time it takes for radio waves to travel from 4 different satellites to the receiver. The System is owned and operated by the US Dept of Defense, but the microwaves can be used by anyone

Answer 28

Global Positioning Systems

Question 29

EM waves with wavelenght from about 400 billion to 10 billion of a meter. Have enough energy to enter skin cells Longer wavelenghts-UVA Shorter wavelenght - UVB rays Boyh can cause skin cancer

Answer 29

Ultraviolet Waves

Question 30

20-50 km above earth Molecules of 3 0 atoms Absorb Suns harmful UV rays Ozone layer decreasing due to CFCs in AC refrigerators and cleaning fluids

Answer 30

Ozone layer

Question 31

Radio stations changes sound to EM waves and then your radio receiver changes the EM waves back to sound waves again

Answer 31

Radio Transmission

Question 32

Usefulness if UV radiation

Answer 32

Helps body make vitamin D for healthy bones and teeth Uses to sterilize medical supplies and equip Detectives use fluoresent powder to find finger prints (absorb UV and glows)

Question 33

EM waves with shortest wavelegth and highest frequency High Energy - go through skin and muscle High level exposure causes cancer

Answer 33

Similarities of X ray and Gamma rays

Question 34

Wm with wavelenght shorter than 10 trillionths of a meter Highest energy can travel through several centimeters of lead Both can be used in radiation therapy to kill diseased cells The composite image shows the all sky gamma ray backgroung

Answer 34

X ray and Gamma ray

Question 35

Radio station change sound to EM waves back to sound waves again

Answer 35

Radio transmission

Question 36

How does radio receive different stations

Answer 36

Each station broad casts at a certain frequency which you tune in by choosing their frequency Carrier wave - the frequency of the EM wave that a station uses Microphones convert sound waves to a changing electric current or electronic signal containing the words and music

Question 37

How does a radio receive different stations?

Answer 37

Microphone convert sound waves to a changing electric current or electronic signak containing the words and music The modified carrier wave vibrate electrons in the stations antennae creating a radio wave that travels out in all directions at the speed of light to your radio antennae