Topic 6 Tadio Waves Flashcards

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1
Q

What are radio waves made by

A

Oscillating charges

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2
Q

What are EN waves made up of

A

Oscillating electric and magnetic fields

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3
Q

What are alternating currents made up of

A

Oscillating charges

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4
Q

What is the charge is oscillate what do they produce

A

Oscillating electric and magnetic field e.g. electromagnetic waves

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5
Q

What is the frequency of the waves produced equal to

A

The frequency of the alternating current

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6
Q

What is the object called which charges oscillate to create radio waves

A

Transmitter

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7
Q

What happens when transmitted radio waves reach the receiver

A

The radio waves are absorbed

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8
Q

What is the energy carried by the waves transfer to

A

Electrons in the material of the receiver

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9
Q

What does the energy cause the elections to do

A

Oscillate and if the receiver is part of a complete electrical circuit it generates an alternating current

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10
Q

What is the current have

A

The same frequency is the radio waves that generated it

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11
Q

How long are radio waves wavelength

A

10 cm

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12
Q

How far can longwave radio wavelength be

A

1-10 km

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13
Q

What can longwave radio wavelengths be used for

A

Transmit signals halfway around the world

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14
Q

Why can longwave radio length be able to talk around the world

A

Cause long wavelength diffracts around curve surfaces and can also diffract around hills and into tunnels

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15
Q

How long are short wave radio signals

A

10 m to 100 m

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16
Q

Why can shortwave radio signals be transmitted

A

They are reflected from the ionosphere (An electric charge Layer in the earths upper atmosphere)

17
Q

What does Bluetooth use

A

Shortwave radio waves to send it over short distances between devices without wires

18
Q

What can medium wave signals do

A

Also be reflected from the ionosphere depending on the atmospheric conditions and time of day

19
Q

What are radio waves used for

A

TV and FM radio transmissions which have very short wavelength
To get a reception you must be in direct sight of the transmitter the signal doesn’t bend or travel far through buildings

20
Q

What makes radio waves

A

An alternating current in a circuit in a transmitter