P1 - topic 2 - radio waves and midcrowaves

Question 1

what waves at used to broadcast TV and radio signals and transmit satellite signals?

Answer 1

radio waves

Question 2

why can long-wave radio be transmitted from London,say, and received halfway around the world?

Answer 2

long wavelengths bend around the curved surface of the earth

Question 3

What kind of wavelengths do the radio waves used for TV and FM radio transmissions haven

Answer 3

short wavelengths

Question 4

To get reception, what must you be in direct sight of?

Answer 4

the transmitter

Question 5

To get reception, why must you be in direct sight of the transmitter?

Answer 5

the signal doesn’t bend around hills of travel fast through buildings

Question 6

can short wave radio signals be received at long distances from the transmitters like long-waves?

Answer 6

yes

Question 7

what is the ionosphere?

Answer 7

an electrically charged layer in the earths upper atmosphere

Question 8

why can short wave radio signals be received at long distances?

Answer 8

because they’re reflected from the ionosphere

Question 9

medium wave signals can also reflect from the ionosphere, depending on what?

Answer 9

atmospheric conditions and time of day

Question 10

microwaves are used for what?

Answer 10

satellite communication and mobile phones

Question 11

communication to form satellites use what waves?

Answer 11

microwaves

Question 12

what kind of microwaves do you need to use to communicate to and from satellites?

Answer 12

ones that can easily pass through the earths watery atmosphere

Question 13

how does a satellite TV work?

Answer 13

1) the signal from a transmitter is transmuted into space
2) it is picked up by a satellite receiving dish orbiting above the earth
3) the satellite transmits the signal back to Earth in a different direction
4) the signal is received by a satellite dish on the ground

Question 14

Why is there sometimes a slight delay between the signal and being sent and received when using a TV satellite?

Answer 14

there is such a long distance for the signal to travel in some cases

Question 15

mobile phone signals travel from your from to the nearest ……. as …….

Answer 15

transmitter as microwaves

Question 16

what do microwave ovens use?

Answer 16

different microwave wavelength from satellites

Question 17

in communications, the microwaves used need to pass through what?

Answer 17

the earths watery atmosphere

Question 18

How do microwaves work?

Answer 18

the microwaves need to be absorbed by water molecules in food to be able to heat up

Question 19

describes what happens when microwaves penetrate food

Answer 19

the microwaves penetrate up to a few centimetres into the food before being absorbed by water molecules. The energy from the absorbed microwaves causes the food to heat up

Question 20

Why is heat energy produced by microwaves conducted to other parts of the food?

Answer 20

because when microwaves penetrate they only do up to a few centimetres into the food

Question 21

what are radio waves mainly used for?

Answer 21

communication