Waves

Question 1

Wave

Answer 1

Is a transfer of energy from one place to another without a transfer of matter.

Question 2

Transverse Wave

Answer 2

In a transverse wave the particles of the medium vibrate perpendicular to the direction of the energy transfer.

Examples of these waves are;
- Light waves
- Earthquake S waves

Question 3

Longitudinal Waves

Answer 3

In a longitudinal wave the particles of the medium vibrate parallel to the direction of the energy transfer.

A compression is where the particles have moved close together.

A rarefaction is where the particles have spread far apart.

Examples of these wave;
- Sound waves
- Earthquake p waves

Question 4

Amplitude (A)

Answer 4

Is the maximum displacement of a particle of the medium from its equilibrium position. Measured in m.

Question 5

Wavelength

Answer 5

Is the distance between two successive particles undergoing the same motion. Measured in m.
In transverse wave is from a crest to another crest.
In a longitudinal wave is from a compression to the next compression of a rarefaction to the next rarefaction.

Question 6

Period (T)

Answer 6

Is the time taken for one complete wave to pass a point.

T = time taken/no. of waves

Question 7

Frequency (f)

Answer 7

Is the number of complete waves passing a point per second.

f = no. of waves/time taken

Question 8

Wave Speed (v)

Answer 8

The speed of a wave is how fast the energy is travelling through a medium. Measure in Ms-1.

Question 9

How are echoes formed?

Answer 9

When waves hit a surface they may bounce off the surface. This is called reflection. When we hear the reflected sound of an echo.

Question 10

Rays

Answer 10

A ray is an arrow drawn to represent the direction in which the energy is being transferred by a wave.

Question 11

Reflection

Answer 11

When a wave hits the surface of a different medium (substance). The proportion of the energy of the wave that reflects depends on the type of medium the wave is hitting.

When a wave reflects;
- Speed does not change
-Frequency does not change
- Wavelength does not change
- Amplitude will decrease

Question 12

Law Of Reflection

Answer 12

angle of incidence (i) = angle of reflection (r)

Question 13

Mirror Diagrams

Answer 13

1. Image
2. Ray from the image to the eye
3. Normal Line (always 90 degree to the mirror)
4. Ray from the mirror to the object
5. Arrow always going into the eye

Question 14

Reflection of Light - Plane Mirrors

Answer 14

When light reflects off a plane mirror, an image of the original object will be formed in the mirror.

Question 15

Refraction

Answer 15

When a wave travels from one medium into another.
- some of the energy bounces of the surface
- some of the energy enters the new medium but the speed of the wave will change

Light slows down when they go into optically dense mediums.

If a wave is slowing down as it enters the new medium it will bend towards the normal.

If a wave is speeding up as it enters the new medium it will bend away from the normal.

Question 16

F.A.S.T

Answer 16

Faster away
Slower towards

Question 17

Optically Density

Answer 17

Optical density is the ability of a material to transmit light through. The more optically dense the bigger the refractive index (n)

Question 18

Snell’s Law

Answer 18

Is used to fine the refractive index (n) of a medium.

n = sin i / sin r

Question 19

Refractive Index (n)

Answer 19

Is a measure of the speed that light will travel in a substance.
n= speed of light in air / speed of light in medium

Question 20

Wavefronts

Answer 20

A wavefront is a line drawn to represent the part of a wave where the medium is undergoing the same motion ( e.g crest of compression) when viewed from above. The distance between wavefronts will be equal to the wavelength.

Question 21

Circular Wavefront