Waves, Light and Sound

Question 1

What are waves and how are they transferred?

Answer 1

Waves are disturbances that transfer energy and are transferred when a wave moves through a substance.

Question 2

What is a mechanical wave and what are the two types.

Answer 2

A mechanical wave is a wave that requires vibrations of a medium to move through. There are two types: Longitudinal and Transverse.

Question 3

What are the two types of waves?

Answer 3

Electromagnetic and Mechanical

Question 4

What is a longitudinal wave?

Answer 4

A longitudinal wave is a mechanical wave in which the particles move parallel to the wave and are formed by a series of compressions and rarefactions. E.g Sound

Question 5

What is a transverse wave?

Answer 5

A transverse wave is a mechanical wave in which the particles move perpendicular to the wave E.g light

Question 6

What is amplitude?

Answer 6

The distance between the crest (top) or the trough (bottom) and the resting point.

Question 7

Is sound a mechanical or electromagnetic wave?

Answer 7

Sound is a mechanical wave because it requires particles to move through.

Question 8

What are longitudinal waves made of?

Answer 8

Compressions and Rarefactions

Question 9

What is frequency and what is its unit of measurement?

Answer 9

Frequency refers to the number of oscillations or cycles a wave completes per second. It is measured in Hz

Question 10

What is wavelength and what is its unit of measurement?

Answer 10

Wavelength is the distance between identical points of two consecutive waves. It is measured in m.

Question 11

What does reflection refer to and when does it occur?

Answer 11

Reflection refer to light bouncing off an object and occurs when a ray of light hits an object and is not absorbed.

Question 12

What is refraction and why does it occur?

Answer 12

The refraction of light is the bending of light rays as they pass from one medium to another, thereby changing the path of the rays, due to light’s different speed in different mediums.

Question 13

What is absorption?

Answer 13

Absorption of light takes place when matter captures electromagnetic radiation, converting the energy of photons to internal energy.

Question 14

What is a transparent material and provide an example.

Answer 14

A transparent material is one that allows all light to pass through e.g. glass

Question 15

What is a translucent material and provide an example.

Answer 15

A translucent material is one that allows a portion of light to pass through e.g. wax paper

Question 16

What is an opaque material and provide an example.

Answer 16

An opaque material is one that allows no light to pass through e.g. concrete

Question 17

What is the relationship between the angle of incidence and the angle of reflection?

Answer 17

They are equal as per the law of reflection.

Question 18

What are compressions and rarefactions?

Answer 18

Compressions are periods in a sound wave where the molecules are closest together, whilst rarefactions are periods where the molecules are furthest apart.

Question 19

What are concave and convex lenses?

Answer 19

A convex lens or converging lens focuses the light rays to a specific point, whereas a concave lens or diverging lens diverges the light rays.

Question 20

What are electromagnetic waves?

Answer 20

Electromagnetic waves are transverse waves formed of simultaneously moving electric and magnetic fields.

Question 21

How does sound travel?

Answer 21

Sound is a type of energy formed by vibrations. These vibrations create sound waves which move through mediums such as air, water and wood. the particles of a substance. It travels by pushing particles of a substance causing a cascading effect as particles collide with adjacent particles.

Question 22

Provide an application of reflection.

Answer 22

Mirrors: Flat mirrors reflect all light and allow us to view reflections
Echoes: Sound waves reflect of surfaces such as walls or buildings and creates echoes. This phenomenon is the basis of sonar technology.

Question 23

Provide an application of refraction.

Answer 23

Concave and Convex Lenses allow us to magnify and shrink images due to the shape of the lens manipulating light as it traverses between differing medium

Question 24

Provide an application of absorption.

Answer 24

Black surfaces absorb more sunlight due to their ability to absorb the greatest amount of wavelengths of light and therefore heat up faster.

Question 25

What is Snells law?

Answer 25

n1 * sin(theta 1) = n2 * sin(theta2)

Question 26

What is the law for the index of refraction?

Answer 26

n = c / v

Question 27

What is the law of frequency?

Answer 27

f = 1 / t

Question 28

What happens to the angle of refraction as light passes from a medium with a higher refractive index to one with a lower refractive index?

Answer 28

The angle of refraction moves away from the normal line.

Question 29

What happens to the angle of refraction as light passes from a medium with a lower refractive index to one with a higher refractive index?

Answer 29

The angle of refraction moves towards the normal line.

Question 30

What unit of measurement is the velocity of a wave measured in?

Answer 30

m/s