Chapter 15- Transmission And Reflection Of Waves

Question 1

Method of energy transfer activity

Answer 1

Using trolleys connected with springs

Energy pulse to one is transferred to all

Question 2

Speed of sound in air (at 20*)

Answer 2

340 m/s

Question 3

Experiment to find speed of sound in air

Answer 3

Using two beam oscilloscope
And a signal generator

Microphone will pick up sounds from speaker and these oscillations will compare to the ones from the speaker itself
Phase difference combined with physical distance will show speed of sound

Question 4

Transverse waves model uses

Answer 4

Model of masses connected by springs and the resolution of forces

Question 5

The pulse moves along the masses with a speed dependent on …

Answer 5

Magnitude of the masses

Tension in the springs

Question 6

Speed of transverse wave eq

Answer 6

C= square root (tension in wire/mass per unit length)

Question 7

Electromagnetic waves through a vacuum speed

Answer 7

3x10^8 m/s

Question 8

Intensity eq

Answer 8

Intensity = power/ area

Question 9

When a wave is incident on an interface between two different media, the energy may be

Answer 9

Absorbed
Transmitted
Or reflected

Question 10

Law of reflection def

Answer 10

States that the angle between the INCIDENT ray and the NORMAL drawn at the point of REFLECTION
Is equal to
The angle between the REFLECTED EA and the NORMAL in the plane of reflection

Question 11

Wavefront

Answer 11

Line or surface in a wave along which all the points are in phase

Question 12

Refraction is caused by

Answer 12

Change in wave speed between two media

Question 13

When speed is increased

Answer 13

Path of waves is directed away from the NORMAL

Question 14

When the wave speed is decreased

Answer 14

The path of the waves is deviated towards the NORMAL

Question 15

In shallow water wave speed is

Answer 15

Slower than in deep water

Question 16

In deep water wave speed is

Answer 16

Faster than in shallow water

Question 17

In a denser medium

Answer 17

Light travels more slowly

Question 18

In a less dense medium

Answer 18

Light travels faster

Question 19

Light and glass

Which is more dense?

Answer 19

Light is

Question 20

Refractive index eq

Answer 20

Refractive index from medium 1 to medium 2 =

Speed in medium 1/ speed in medium 2

Question 21

What is Snell’s law

Answer 21

States that the refractive index for a wave travelling from one medium to another is given by the expression

Sin[]1/ sin[]2 = v1/ v2 = 1n2

N1 Sin[]1= N2 Sin[]2

Question 22

Does refraction occur for all waves?

Answer 22

YES

Question 23

Critical angle def

Answer 23

Angle above which total internal reflection occurs

Question 24

Snells law simple

Answer 24

N1/n2 = sin[]2 / sin[]1

Question 25

Critical angle eq

Answer 25

Sin C= n2/ n1

Question 26

Converging lens shape

Answer 26

()

Question 27

Diverging lens shape

Answer 27

)(

Question 28

Focal point def

Answer 28

Point of a lens is the point where parallel rays of light will meet, or appear to diverge from, after passing through the lens

Question 29

Converging lens form a

Answer 29

Real focus

Question 30

Diverging lens form a

Answer 30

Virtual focus

Question 31

Focal length

Answer 31

Distance between optical centre of the lens and the focal point

Question 32

Power of a lens relates to

Answer 32

The ability of the lens to deviate rays of light through large angles

Question 33

The more powerful a lens

Answer 33

The shorter the focal length

Question 34

Power of lens eq

Answer 34

1/ focal length (m)

Question 35

Power of lens unit

Answer 35

Dioptre M^-1

Question 36

Total power calculated by

Answer 36

The sum of all the lenses

Question 37

Types of image created (2)

Answer 37

Virtual | Real

Question 38

Principle axis

Answer 38

A line that passes normally through the optical centre of the lens

Question 39

Optical centre

Answer 39

The centre of a lens is the point through which rays of light will pass without deviation

Question 40

The lens equation

Answer 40

1/u + 1/v = 1/f All distances given positive values if real images formed ``` Converging = positive value focal length Diverging = negative value focal length ```

Question 41

Key words to describe reflected images

Answer 41

Enlarged, smaller Real, virtual Inverted, erect

Question 42

Plane polarised waves def

Answer 42

Are transverse waves in which the oscillations occur in a single plane

Question 43

Polarised waves can only work for oscillations in

Answer 43

One direction | Horizontal or vertical

Question 44

Polarising filter

Answer 44

Filters waves in certain oscillation decoration

Question 45

Longitudinal waves cannot be polarised because

Answer 45

The waves have particles that have no components of oscillations in the planes perpendicular to the direction

Question 46

How to polarise microwaves using transmitter

Answer 46

Turn receiver 90* rotation to polarise microwaves or radio waves

Question 47

How is a light polarisation filter made

Answer 47

Made from polymers | With the molecular chains aligned in one direction

Question 48

Stress analysis how

Answer 48

Put load-bearing components under stress View through crossed sheets of Polaroid Multicoloured interference stress patterns analysed to detect potential regions of weakness

Question 49

A scans abbreviated from

Answer 49

Amplitude scans

Question 50

B scans abbreviated from

Answer 50

Brightness scans

Question 51

Pulse- echo techniques

Answer 51

Used to calculate speed of sound And then to help medicine and scans for things As well as in underwater exploration

Question 52

What to remember about distance with pulse echo techniques

Answer 52

The distance is doubled in the experience

Question 53

Type of electromagnetic wave used in pulse echo techniques

Answer 53

Ultrasound

Question 54

Amplitude scans used to

Answer 54

Determine depth of boundaries between tissues or bone and tissue Coupling gel needed so very little is reflected from the skin

Question 55

Brightness scans used to

Answer 55

Detect position of reflecting boundary | They give a display/ image