C3- Waves

Question 1

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

Answer 1

1. Transverse
2. Longitudinal

Question 2

Define wavelength

Answer 2

Distance between two successive crests/troughs

Question 3

Define frequency

Answer 3

Number of complete waves per second

Question 4

What is frequency measured in?

Answer 4

Hertz (Hz)

Question 5

Define Wave Speed

Answer 5

Distance moved by a point on the wave in 1 second

Question 6

Define Amplitude

Answer 6

Height of Crest or Depth of trough from the equilibrium

Question 7

Wave equation

Answer 7

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

Question 8

Define Wavefront

Answer 8

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

Question 9

Define ray

Answer 9

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

Question 10

Equation of reflection

Answer 10

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

Question 11

What is the cause of refraction?

Answer 11

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

Question 12

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

Answer 12

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

Question 13

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

Answer 13

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

Question 14

What is diffraction?

Answer 14

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

Question 15

What is parallel beam of light?

Answer 15

all the beams are travelling straight

Question 16

What is a beam?

Answer 16

Streams of lights shown by several rays

Question 17

What is divergent beam of light?

Answer 17

all the beams are dispersing into different directions

Question 18

What is convergent beams of light?

Answer 18

All the beams are combining at one point

Question 19

What is the Normal?

Answer 19

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

Question 20

What is the speed of light?

Answer 20

3x10⁸ m/s

Question 21

What is a real image

Answer 21

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

Question 22

What is a virtual image

Answer 22

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

Question 23

Is the image on a mirror real or virtual?

Answer 23

Virtual (rays are reflected)

Question 24

What is the refractive index (n)?

Answer 24

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

Question 25

Refractive index of glass

Answer 25

1.5

Question 26

Refractive index of water

Question 27

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

Answer 27

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

Question 28

What is the formula for refractive index involving sin?

Answer 28

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

Question 29

What is the Critical angle?

Answer 29

when the refracted angle is 90°

Question 30

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

Answer 30

total internal reflection- light reflects inwards towards the medium

Question 31

Equation for Critical angle

Answer 31

Sin(c)= 1/n