Physics test 2

Question 1

23What is the definition of refraction?

Answer 1

The change in direction of a wave when moving into a different medium

Question 2

Where does refraction occur?

Answer 2

In the interface (Boundary) between the two media

Question 3

What is the Normal line?

Answer 3

the line that it as a right angle to the interface

Question 4

When is the only time refraction doesn’t occur when changing medium?

Answer 4

Light traveling along the normal does not change direction when it goes into a different medium

Question 5

What are the two factors that change how much the bend of light is?

Answer 5

The bend depends on how fast the light travels in the two media and the angle of the light hitting the interface

Question 6

What are the four different outcomes when a wave reaches an interface?

Answer 6

It can be reflected
refracted
transmitted
absorbed

Question 7

Definition of reflected?

Answer 7

the wave ‘bounces’ of

Question 8

Definition of refracted?

Answer 8

the wave passes into a new material but changes the direction in which it is travelling

Question 9

Definition of Transmitted?

Answer 9

the wave passes through the material and is not absorbed or reflected

Question 10

Definition of absorbed?

Answer 10

the wave disappears as the energy it is carrying is transferred to the material

Question 11

How do prisms split all the colours in white light?

Answer 11

Since all colours change speed by different amounts when they travel from air to glass this means they are refracted by varying angles

Question 12

When we hear a different pitch what does it mean?

Answer 12

It means our ears are hearing different levels of frequencies of sound (not the wavelength)

Question 13

A sound has the same pitch if it reaches us through a solid or air so when a sound waves enters a different material what changes?

Answer 13

It is the wavelength and velocity that changes , not the frequency

Question 14

Are sound waves longitudinal or transverse?

Answer 14

longitudinal

Question 15

What determines how vibrations of different frequencies will affect solids?

Answer 15

The shape and properties ( such as density and stiffness)

Question 16

What are the 6 steps that occur when a sound wave is created and reaches the brain?

Answer 16

First the sound wave enters the Ear Canal

Second the Eardrum is a thin membrane.
Sound waves make it vibrate.

Third Vibrations are passed onto tiny bones which amplify the vibrations

Fourth Vibrations are passed on the liquid inside the Cochlea

Fifth Tiny hairs inside the Cochlea detect these vibrations and create electrical signal called impulses

Lastly these impulses travel along neurons in the auditory nerve to reach the brain

Question 17

What is the Cochlea?

Answer 17

The Cochlea is a coiled tube containing a liquid. It can detects different frequencies of sound reaching the ear

Question 18

Fill in the blank. (2)

Human ears can detect sounds from …… Hz to ……….. Hz

Answer 18

20 Hz to 20,000 Hz

Question 19

How does the Cochlea work?

Answer 19

The cochlea contains a membrane which is located in the middle of the tube. At the base it is stiffer and thicker while at the apex it is thinner. The part that vibrates depends on the frequency of the sound wave in the liquid inside the cochlea this is because different thicknesses of the membrane vibrate best at different frequencies. on this membrane there are Thousands of hair cells that are connected to a neuron that sends impulses to the brain . The brain then interprets signals from different neurons as different pitches of sound

Question 20

What is Ultrasound?

Answer 20

Sounds made by waves with higher frequencies than 20000H (20kHz)

Question 21

How does sonar equipment on ships/submarines work?

Answer 21

A loudspeaker on the ship emits a pulse of ultrasound. this spreads out through the water and some of it is reflected by the sea bed. a special microphone on the ship detects the echoes, out and the echoes returning. the distance travelled by the sound wave can be worked out using this equation:

Distance - speed x Time

Question 22

What is the prepose of the gel used when scanning the fetus?

Answer 22

The gel is used to stop the ultrasound just reflecting from the skin

Question 23

What is infrasound?

Answer 23

Sound with a frequency less than 20 Hz are too low for humans to hear

Question 24

Which seismic wave is longitudinal and which is transverse?

Answer 24

P waves are longitudinal
S waves are transverse

Question 25

Can transverse waves travel through solids liquids and gases ?

Answer 25

No , only solids

Question 26

Why do S wave shadow zones occur?

Answer 26

The occur due to the liquid core which s waves are unable to pass through

Question 27

Why do P wave shadow zone occur?

Answer 27

They occur due to the 8 liquid inner and solid outer core refraction the p waves.

Question 28

What is the law of reflection?

Answer 28

When waves are reflected, the angle of reflection is equal to the angle of incidence

Question 29

What is a ray diagram?

Answer 29

a ray diagram is a way of modelling what happens when light is reflected of refracted

Question 30

when does total internal reflection occur?

Answer 30

When the angle of incidence is equal to the critical angle, the refracted light passes along the interface (Boundary) then if the angle of incidence is even greater than the critical angle then the light is completely reflected inside the block

Question 31

What’s the difference between luminous and non-luminous?

Answer 31

You see luminous objects because the light they give off enters your eyes while Non-luminous objects because they reflect lights

Question 32

What is diffuse reflection?

Answer 32

Most material have rough surfaces if you examine them closely so the reflected light is scattered in all directions

Question 33

What is specular reflection?

Answer 33

When smooth surfaces, such as mirrors reflect light evenly

Question 34

Why do we see an object as red?

Answer 34

When white light hits a coloured surface some of the colour that make it up are absorbed and some are reflected a red object looks red because it reflects red light and absorbes all the other colours

Question 35

What is a filter?

Answer 35

A filter is a piece of transparent material that absorbs some of the colour in white light. For example a blue filter transmits(Allows through) blue light and absorbs all the other colours.

Question 36

What is a lens?

Answer 36

A lens is a piece of transparent material that is shaped in order to refrct light in a particular way.

Question 37

What is a converging lens?

Answer 37

A Lens that is is fatter in the middle than at the edges. it makes parallel rays of light converge at the focal point

Question 38

What is a diverging lens?

Answer 38

A lens which is thinner in the middle than the edges. The focal point is the point from which the rays seem to be coming from after passing through the lens

Question 39

What is the focus length?

Answer 39

The distance between the focal point and the center of the lens

Question 40

Describe how we see the image through the diverging lens?

Answer 40

Virtual
upright
diminished

Question 41

Describe how we see the image through the Converging lens?

Answer 41

real
inverted
diminished

Question 42

Describe how we see the image through the Converging lens when the object is close to the lens?

Answer 42

Virtual
upright
magnified

Question 43

Which type of shape is diverging concave or convex?

Answer 43

Concave

Question 44

Which type of shape is converging concave or convex?

Answer 44

Convex

Question 45

What is the critical angle?

Answer 45

the critical angle is the angle of incidence for which the angle of refraction is 90 degrees (along the interface)