P1.5 EM Spectrum and Soud Flashcards

1
Q

What do waves do?

A

All waves move energy from one place to another and can be either;
transverse
or
longitudinal.

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2
Q

Define longitudinal waves.

A

Particles move in same direction as movement of wave have compression’s and rarefractions.

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3
Q

Define transverse waves.

A

Particles move 90 degrees to direction of wave and have peaks and troughs.

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4
Q

What 2 things do electromagnetic waves have in common?

A

Electromagnetic waves are transverse and travel at the same speed through a vacuum 300,000km/s.

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5
Q

State the order of the electromagnetic spectrum.

A
Gamma rays.
X-rays.
Ultraviolet rays.
Visible light.
Infra-red rays.
Microwaves.
Radiowaves.
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6
Q

Are mobile phones harmful to some users?

A

There is some evidence to support that mobile phones are harmful so some users.
However, there is evidence to support the contrary.

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7
Q

What is a use for radio waves, microwaves, infra-red and visible light?

A

Can be used for communication.

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8
Q

How do we communicate with satellites?

A

Microwaves can pass through the Earth’s atmosphere.

Radio waves cannot.

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9
Q

How are electromagnetic waves used in optical fibres?

A

Infra-red and visible light can be used to send signals along optical fibres and so travel in curved paths.

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10
Q

What is the ‘normal’ line?

A

The ‘normal’ is a line 90 degrees to the mirror at the point of reflection.

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11
Q

What is the law of reflection?

A

The angle of incidence is equal to the angle of reflection.

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12
Q

How do we describe the image produced in a plane mirror?

A

The image produced in a plane mirror is virtual, upright and laterally inverted.

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13
Q

Explain what happens during refraction.

A

Wave-fronts change direction when they enter a material at an angle and move at a different speed.

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14
Q

Explain what happens during diffraction.

A

Waves spread out when they come to an edge or a gap.

Diffraction happens more if the gap is the same size as the wavelength of the wave.

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15
Q

Define frequency.

A

A number of waves passing a point per second.

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16
Q

Define wavelength.

A

Distance between 2 neighbouring peaks.

17
Q

Define amplitude.

A

Distance from peak to line of equilibrium.

18
Q

What are sound waves?

A

Longitudinal waves and cause vibrations in a material, which are detected as sound.

19
Q

What determines the pitch and loudness of a sound?

A

The pitch of a sound is determines by its frequency and loudness by its amplitude.

20
Q

What are echos?

A

Reflections of sounds.