C3- Waves

Question 1

What are the two types of progressive waves? [2]

Answer 1

1. Transverse
2. Longitudinal

Question 2

Transverse waves [2]

Answer 2

1. Has peaks and troughs
2. vibrations are at right angles to the direction of travel

Question 3

Longitudinal waves [2]

Answer 3

1. Consists of compressions and rarefactions
2. vibrations are in the same directional as the directions of travel

Question 4

Define wavelength

Answer 4

Distance between two successive crests/troughs

Question 5

Define Wave motion

Answer 5

transfer of energy from one point to another without the transfer of matter

Question 6

Define frequency

Answer 6

the distance travelled by a wave each second

Question 7

What is frequency measured in?

Answer 7

Hertz (Hz)

Question 8

Define Wave Speed

Answer 8

Distance moved by a point on the wave in 1 second

Question 9

Define Amplitude

Answer 9

Height of Crest or Depth of trough from the equilibrium

Question 10

Wave equation

Answer 10

Wave speed (v) = Frequency(f) x Wavelength (⁁)

Question 11

Define Wavefront

Answer 11

Straight line where the wave has the same phase at all points

Question 12

Define ray

Answer 12

Line draw at right angles to a wavefront showing the direction of travel.

Question 13

Equation of reflection

Answer 13

Angle of incident (i) = angle of reflection (r)
(Same speed too)

Question 14

What is the cause of refraction?

Answer 14

The change of speed in different mediums cause the light ray to change speed

Question 15

How does the ray act when it moves from a less dense to more dense medium?

Answer 15

They bend towards the normal
(light slows down due to smaller wavelengths)

Question 16

How does the ray act when it moves from a more dense to less dense medium?

Answer 16

they bend away from the normal
(light fastens due to bigger wavelengths)

Question 17

What is diffraction?

Answer 17

When straight waves meet at narrow gaps and create circular wavefronts
(can occur at the edge of an obstacle)

Question 18

What causes more diffraction? [2]

Answer 18

1. Narrower the gap
2. Greater wavelength

Question 19

What is a ripple tank?

Answer 19

shallow tank of water to study wave motion

Question 20

What is parallel beam of light?

Answer 20

all the beams are travelling straight

Question 21

What is a beam?

Answer 21

Streams of lights shown by several rays

Question 22

What is divergent beam of light?

Answer 22

all the beams are dispersing into different directions

Question 23

What is convergent beams of light?

Answer 23

All the beams are combining at one point

Question 24

What is the Normal?

Answer 24

A line perpendicular to the mirror at the point where incident ray strikes (90°)

Question 25

What is the speed of light?

Answer 25

3x10⁸ m/s

Question 26

What is a real image

Answer 26

an image that can be produces on a screen and is formed by rays that pass through the screen

Question 27

What is a virtual image

Answer 27

a virtual image is produces by rays that seem to come from the object but do not pass through it.

Question 28

Is the image on a mirror real or virtual?

Answer 28

Virtual (rays are reflected)

Question 29

What is the refractive index (n)?

Answer 29

the ratio of light speed in air to light speed in the medium

Question 30

Refractive index of glass

Answer 30

1.5

Question 31

Refractive index of water

Question 32

What is the formula for refractive index involving speed of light?

Answer 32

n= speed of light in air/ speed of light in medium

Question 33

What is the formula for refractive index involving sin?

Answer 33

n = sin(i)/ sin(r) i= angle of incidence r= angle of refraction

Question 34

What is the Critical angle?

Answer 34

when the refracted angle is 90°

Question 35

What happens when angle of Incidence goes greater than critical angle?

Answer 35

total internal reflection- light reflects inwards towards the medium

Question 36

Equation for Critical angle

Answer 36

Sin(c)= 1/n