Chapter 4

Question 1

What is a wave ?

Answer 1

A disturbance that travels through a medium and transports energy (not matter)

Question 2

What two waves is there

Answer 2

Transverse and longitudinal

Question 3

What does a transverse wave do

Answer 3

Propagates/Moves perpendicular to the motion of its medium

Question 4

What does a longitudinal wave do

Answer 4

Moves parallel to the motion of its medium.

Question 5

What is the amplitude

Answer 5

Max distance travelled from the equilibrium to the highest or lowest part of the wave in a transverse ( the higher amplitude= denser compression in a longitudinal)

Question 6

What is wave length

Answer 6

Length of a waves complete cycle

(λ)= symbol for wavelength

Question 7

What is frequency and what is the formula

Answer 7

The number of cycles per unit of time (units it is measured in: Hertz Hz)

Formula: speed= frequency x wavelength

Question 8

What is the highest and lowest point of a transverse wave called

Answer 8

Highest is crest and lowest is through

Question 9

What are the three parts of a longitudinal wave and what do they do/look like

Answer 9

Region of refraction= area where wave isn’t compressed close together and the density is low
Region of compression = area where the wave is compressed close together
Cycle= idk fr like wavelength but in a longitudinal wave

Question 10

What is a mechanical wave

Answer 10

A wave that requires a medium in order to propagate

Question 11

What is a electromagnetic wave

Answer 11

A wave that can travel in both a vacuum and a medium

Question 12

What does the electromagnetic spectrum do

Answer 12

Organizes all electromagnetic waves according to their wavelength and their frequency

Question 13

What 6 waves are on the electro magnetic spectrum and one example per wave

Answer 13

Radio :phone
Infrared: night vision goggles
Visible light: lightning
Ultraviolet rays:treatment of certain ailments
X-rays:airport baggage inspection
Gamma rays:cancer treatment

Question 14

What is sound

Answer 14

A longitudinal wave produced by vibration of an object and transmitted to the object’s environment

Question 15

What is the decibel scale

Answer 15

A scale that represents the perception of the intensity of sound by the human ear

Question 16

The speed of sound varies from ONE MEDIUM TO ANOTHER (<— lowk important) in the air, what is the speed of sound

Answer 16

About 340 m/s or 1224 km/h

Question 17

What does the intensity of sound depend on and what is the intensity measured in

Answer 17

It depends on the amplitude of the sound wave and it is measured in DECIBLES (DB)

Question 18

What do sound tones correspond to and what is it measured in

Answer 18

They correspond to the frequency and it is measured in Hz

Question 19

What is light

Answer 19

An electromagnetic wave that is visible to the human eye

Question 20

What is reflection

Answer 20

The rebounding of light that occurs when a light ray hits a different medium and bounces back to the medium from which it came from

Question 21

What is the incident ray

Answer 21

Ray that contacts the surface of an object

Question 22

What is the reflected ray

Answer 22

Ray that rebounds

Question 23

What is the normal

Answer 23

A line perpendicular to the surface at the point of reflection

Question 24

What is the angle of incidence and angle of reflection

Answer 24

The angle of incidence is the angle formed by the incident ray and the normal.
The angel of reflection is the angle formed by the reflected ray and the normal

Question 25

What are the laws of reflection

Answer 25

•The angle of incidence is always equal to the angle of reflection •The incident ray and reflected ray are always on the same plane (Look at picture in notebook)

Question 26

What are the two types of reflection

Answer 26

Diffuse and specular

Question 27

Behaviour of diffuse light rays

Answer 27

Parallel light waves are reflected in all directions

Question 28

Behaviour of specular light rays

Answer 28

When parallel light rays strike a smooth surface, the reflected rays are also parallel

Question 29

What are the characteristics of a reflected imagine in a plane mirror

Answer 29

•The image appears to be behind the mirror, at a distance equal to the distance between the mirror and the reflected object •The image is a virtual image •The image is the same size as the objects •The image is horizontally inverted, that is the left side of the image ( look at picture in note book)

Question 30

What is refraction

Answer 30

The deviation of a light ray as it passes from one transparent medium to another

Question 31

What is a lens

Answer 31

An object made of transparent materials that have at least one curved surface

Question 32

What is the focal point of a converging lens

Answer 32

The real point where the refracted rays actually meet when the incident rays run parallel ( look at picture in note book)

Question 33

What are the 3 principle rays in a converging lens

Answer 33

1- Ray that travels parallel to the principal axis it is refracted through the principal focal point. 2- Ray that travels straight through the optical centre of a lens it is not refracted. 3- Ray that travels straight through the secondary focal point is refracted parallel to the principal axis.

Question 34

the final image formed by a converging lens has different characteristics depending on what? and what are the characteristics ?

Answer 34

•It depends on the object in relation •the characteristics can be the type of image ,its size, its position, and its orientation.

Question 35

What is the focal point of a DIVERGING lens

Answer 35

The virtual point where the refracted light rays appear to emanate when incident rays run parallel (look at picture in notebook)

Question 36

What are the 3 principle rays in a diverging lens

Answer 36

1- Ray running parallel to the principal axis is refracted, appearing to originate from the focal point. 2- Ray passing through the optical centre of a lens does not deviate. 3- Ray that travels toward the secondary focal point is refracted parallel to the principal axis.

Question 37

The image obtained by a diverging lens is always what ? And where is the image always located

Answer 37

•The same, irrespective of the position of the object •It is always located between the principal focal point and the lens.

Question 38

GO IN LAST PAGES OF OUR NOTES FOR PICTURES OF 3 PRINCIPLE RAYS AND ANGLE STUFF

Answer 38

Br br patapim