# Topic 6 - Waves Flashcards

1
Q

What are waves?

A

Waves transfer energy from one pack to another without transferring matter.

2
Q

How can wave motion be shown?

A

They can be shown by the vibrations of a spring or by water waves.

3
Q

How can wave motion be shown in waves?

A

When a wave travels along the surface of water, a cork floating on the surface of the water will only move up and down as the wave passes.

4
Q

How can wave motion be shown in springs?

A

Hold one end of a horizontal spring in a fixed position and move the other end of the spring up and down. We can observe a wave moving from the end we are holding towards the fixed end of the spring.

5
Q

What is the formula for wave speed?

A

Wave speed = frequency x wavelength

6
Q

What is the unit for wave speed?

A

Metres per second (m/s).

7
Q

What is a transverse wave?

A

Transverse waves cause the particles in the medium (the substance that the wave travels through) to vibrate at right angles (perpendicular) to the direction of the wave’s motion.

8
Q

What are examples of longitudinal waves?

A

P-waves - pressure waves created during earthquakes
Pushing and pulling springs - create these waves
Sound waves

9
Q

What is a longitudinal wave?

A

Longitudinal waves cause the particles to move in the same direction relative to the direction of the longitudinal wave (parallel).

10
Q

What is the frequency of a wave?

A

The frequency of a wave is the number of times a point on the wave oscillates per second.

11
Q

What is the unit for the frequency of a wave?

A

Frequency is measured in Hertz (Hz).

12
Q

What is the formula for the frequency of a wave?

A

Frequency = oscillations / time

13
Q

What is the wavelength?

A

The wavelength is the distance between two adjacent wavefronts. For transverse waves, this is the distance between two peaks of adjacent waves. Measured in metres.

14
Q

What is the amplitude?

A

The amplitude of a wave is the largest distance that a point on the wave moves from its rest position.

15
Q

If sound is a longitudinal wave, what can it be?

A

It can be refracted, reflected, absorbed and transmitted.

16
Q

How can sound travel through solids?

A

They can travel through solids by causing vibrations in the solid.

17
Q

How is sound produced?

A

Sound is produced by the vibrations of particles in a medium, the vibrations mean that sound waves travel in a series of compressions (where the medium is squashed together) and rarefractions (where the medium is stretched apart).

18
Q

How is the speed of sound measured in the echo experiment from Person 1’s perspective?

A

Two people stand a measured distance from a tall vertical wall. This distance should ideally be about 100 metres. The first person bangs two wooden blocks together to make a sharp sound and repeats this every time the echo is heard.

19
Q

How is the speed of sound measured in the echo experiment from Person 2’s perspective?

A

Starting counting from zero, the second person uses a stopwatch to measure the time taken for a number of claps. In the time between two successive claps, the sound travels to the wall and back.

20
Q

How is the speed of sound calculated?

A

Speed of sound = distance to wall x 2 x number of claps (n) / time taken for n claps.

21
Q

What are electromagnetic waves?

A

They are transverse waves that travel at the same speed in a vacuum.

22
Q

What can we assume about the speed of electromagnetic waves?

A

It is the same speed in the air and when in a vacuum.

23
Q

What is the electromagnetic specturm?

A

It can be split into seven types of wave.

24
Q

What waves are in the EM spectrum ordered from high to low frequency?

A

Gamma, x-rays, ultraviolet, visible, infrared, microwave and radio waves.