Optics

Question 1

What is light?

Answer 1

Electromagnetic radiation which is visible to the human eye

Question 2

What do electromagnetic waves consist of?

Answer 2

A magnetic field and an electric field traveling together

Question 3

What angle are magnetic fields and electric fields displaced at to each other?

Answer 3

90˚ following a sinusoidal pattern

Question 4

The colour of light that can be perceived by the human eye are actually differences in?

Answer 4

Frequency or wavelength of the electromagnetic waves falling onto the retina

Question 5

What colour does light go with a higher frequency of light?

Answer 5

Blue

Question 6

When the frequency of light is too high for humans to see what happens to it?

Answer 6

It becomes ultra violet

Question 7

What colour does light go with a lower frequency of light?

Answer 7

Red

Question 8

What happens to the light when the frequency becomes too low?

Answer 8

It becomes infra-red

Question 9

Can humans see ultra violet or infra-red?

Answer 9

No

Question 10

What are light waves measured in?

Answer 10

Nanometres and angstroms

Question 11

In nanometres what is the scale that humans can see in wavelengths?

Answer 11

400nm-700nm

Question 12

Light is a type of?

Answer 12

Wave

Question 13

What is the speed of light in a vacuum?

Answer 13

186,000miles per second or 300,000,000 metres per second

Question 14

What happens to light speed when it travels through water, glass, and diamonds compared to a vacuum?

Answer 14

It gets slower

Question 15

When light passes through matter the speed is?

Answer 15

Reduced

Question 16

What is the equation for speed of light?

Answer 16

Wavelength x frequency

Question 17

In an equation If the speed of light is not given to you what must you do?

Answer 17

Assume its traveling in a vacuum at 3x10^8 m/s

Question 18

What is reflection?

Answer 18

That a light wave bounces back when it hits a different medium

Question 19

The angle of incidence is equal to?

Answer 19

The angle of reflection

Question 20

The incident ray, reflection ray, and normal all lie within?

Answer 20

The same plane

Question 21

In relation to reflection what is does the word plane refer to?

Answer 21

A two-dimensional space

Question 22

What are the two ways an image can be created by a reflection?

Answer 22

Real or virtual

Question 23

What is a real image?

Answer 23

Can be projected onto a screen or wall

Question 24

What is a virtual image?

Answer 24

An image that can only be seen looking into the optics and cannot be projected

Question 25

When a plane mirror is used what happens to the formed image?

Answer 25

-its the same size -virtual image -same distance behind as in front -back to front but right way up

Question 26

What are the two types of spherical mirrors?

Answer 26

Concave and convex

Question 27

What direction does a convex mirror curve?

Answer 27

Outward, towards the light source

Question 28

What type of spherical mirror is used to make the image appear smaller?

Answer 28

Convex

Question 29

What type of spherical mirror is used to provide a wider field of view?

Answer 29

Convex

Question 30

What direction does a concave mirror curve?

Answer 30

Inwards, away from the light source

Question 31

What happens to an image if it is close to a concave mirror?

Answer 31

-magnified -upright -virtual

Question 32

What happens to an image if it is far away from a concave mirror?

Answer 32

-diminished -inverted -real image

Question 33

What is refraction?

Answer 33

Change in direction of a light wave when it enters a different medium

Question 34

Why does refraction happen?

Answer 34

When light crosses the boundary between two mediums, the change in speed causes the light to change direction

Question 35

What is the only exception for refraction not to take place?

Answer 35

When the ray is perpendicular to the surface (light changes speed but not direction)

Question 36

What is the refractive index of a material?

Answer 36

The ratio of the speed of light in a vacuum compared to the speed of light in the material

Question 37

What does a bigger refractive index mean?

Answer 37

The more light will bend when entering and leaving the material

Question 38

What is the equation for the refractive index?

Answer 38

Speed of light in a vacuum over the speed of light in the material

Question 39

What is snells law?

Answer 39

A formula used to describe the relationship between the angles of incidence and refraction

Question 40

What is a lense?

Answer 40

An optical device that refracts light

Question 41

What is a lense used for?

Answer 41

To form an image

Question 42

How do lenses form images?

Answer 42

The same way as curved mirrors but by refraction rather than reflection

Question 43

What are convex lenses also referred to as?

Answer 43

A converging lens

Question 44

What is special about the thickness of a convex lens?

Answer 44

It is thicker at its centre compared to the edges

Question 45

What type of image does a convex lens form?

Answer 45

A real or virtual image depending on the positions of the object and the observer

Question 46

What is a concave lens also referred to as?

Answer 46

Diverging lens

Question 47

What is special about the thickness of a concave lens?

Answer 47

It is thinner at its centre

Question 48

What image is formed by a concave lens?

Answer 48

Always upright, virtual, and diminished

Question 49

What does fibre optics transmit?

Answer 49

Light through fibres

Question 50

How does fibre optic cables work?

Answer 50

The information is converted to a light signal and transmitted along a fibre at the speed of light. Once at the end the signal is reconverted into information

Question 51

How big is a fibre optic strand?

Answer 51

The same as a piece of hair

Question 52

What are fibre optic strands made from?

Answer 52

Glass or plastic

Question 53

What are the advantages that fibre optics have over metal wires?

Answer 53

-lighter and smaller -carry more information -intrinsically safer

Question 54

What are the main disadvantages of fibre optic?

Answer 54

Difficult to terminate and difficult to repair due to size

Question 55

Why does fibre optic strands have a core with a high refractive index?

Answer 55

So all the light is reflected back into the fibre

Question 56

Why does a fibre optic strand have cladding with a low refractive index?

Answer 56

So as little light is lost

Question 57

What is internal reflection?

Answer 57

The core and cladding strengths in a fibre optic cable

Question 58

Where is the greatest loss of signal occur in fibre optics?

Answer 58

At connectors and couplings