Waves

Question 1

What are Mechanical waves?

Answer 1

Waves that need a medium to travel through. E.g. sound, water waves and seismic waves

Question 2

What are Electromagnetic waves?

Answer 2

Vibrating electromagnetic fields which can travel through space without a medium. E.g. light, radio waves, microwaves and x-rays

Question 3

Describe Longitudinal waves.

Answer 3

Areas of compression and rarefaction.
Direction of vibration is parallel to direction of wave travel.
E.g. sound waves, Primary Seismic waves

Question 4

Describe Transverse waves

Answer 4

Oscillations with amplitudes
Direction of vibration is perpendicular to direction of wave travel
E.g. Electromagnetic waves, Secondary Seismic Waves

Question 5

What is Polarisation?

Answer 5

When all the waves in a ray have the same orientation. They oscillate in the same plane.

Question 6

What is superposition?

Answer 6

The addition of the amplitudes of two waves of the same type exist in the same plane

Question 7

What are stationary waves?

Answer 7

Waves with nodes (fixed points) and anti-nodes

Question 8

What is the equation for the number of nodes, anti-nodes and wavelength of the harmonic?

Answer 8

harmonic = n
nodes: n+1
anti-nodes: n
wavelength: (2/n)L

Question 9

What is the first harmonic?

Answer 9

The fundamental mode of vibration

Question 10

How is a node formes?

Answer 10

When two progressive waves travelling in opposite directions and displace (superposition) - amplitudes add to equal 0