Waves pt1 Flashcards Preview

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Flashcards in Waves pt1 Deck (17)
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1
Q

Transverse

A

The wave is perpendicular to the force applied

Waves up and down e.g. a spring

2
Q

Longitudinal

A

Oscillations parallel to energy transfer

Compresses and extends e.g. ultrasound in air

3
Q

Drawings

A

Transverse goes up and down, longitudinal have flat lines

4
Q

Period

A

1/ frequency

5
Q

Amplitude

A

Maximum displacement of a point on the wave from its undisturbed position

6
Q

Wave speed=

A

Frequency x wavelength

7
Q

What can all waves be?

A

Be Absorbed, reflected and transmitted

8
Q

Reflecting

A

Angle of incidence = angle of reflection

9
Q

Normal

A

A perpendicular line to the surface at the point of incidence (dotted line)

10
Q

Speculation reflection

A

When a wave is reflected in a single direction by a smooth surface to make a clear line of reflection

11
Q

Diffuse reflection

A

When a wave is reflected by a rough surface to scatter the reflected rays in a lot of direction (surface appears matte and there won’t be a clear reflection)

12
Q

Refraction

A

When a wave crosses a boundary between materials and changes direction
The density affects the extremity of this
Quicker waves through less dense objects are refracted away from the normal

13
Q

What are radio waves made of (1/2)

A

Oscillating charges and magnetic fields
AC are made up of oscillating charges to produce these
Frequency of ac = wave frequency
Can produce radio waves with a transmitter in an ac circuit

14
Q

What are radio waves made of (2/2)

A

Absorbed by a receiver
Energy from waves is transferred to electrons
Electrons oscillate to generate an ac in a circuit
Has the same frequency as the waves that generated it

15
Q

Radio waves

A

EM radiation with wavelengths over about 10cm
Lamb radio waves have wavelengths of 1-10km can diffract around curves
Short waves (10-100m) are reflected from the ionosphere and medium waves depending on time of day

16
Q

Dangers of EM waves

A

The high frequency waves emit lots of energy so can cause lots of damage
UV Damages surface cells and can lead to sunburn and cause skin to prematurely age and could cause blindness or skin cancer
X-rays and gamma are ionising so could cause gene mutation or cell destruction and cancer

17
Q

Radiation doses are measured in

A

Sieverts (generally millisieverts(1mSv:1000Sv))