Waves

Question 1

What are some applications of refraction?

Answer 1

Catseyes, Endoscope, Submarine periscopes, Optical fibres, Bike reflector etc.

Question 2

What two types of lenses are there?

Answer 2

Convex and Concave

Question 3

What happens when the angle of incident is smaller than the critical angle?

Answer 3

The angle refracts

Question 4

What happens when the angle of incident is equal to the critical angle?

Answer 4

There is bother refraction and reflection

Question 5

What happens the angle of incident is larger than the critical angle?

Answer 5

There is only reflection

Question 6

What is a trait of the amplitude along a progressive wave?

Answer 6

It stays the same along every part of the wave

Question 7

What is a trait of the amplitude on a stationary/standing wave?

Answer 7

The amplitude varies

Question 8

What is a node?

Answer 8

A point along a stationary wave with zero amplitude

Question 9

What is an antinode?

Answer 9

The point of maximum displacement from the equilibrium in a stationary wave

Question 10

What is absolute refractive index?

Answer 10

When light is traveling from a vacuum’s into glass

Question 11

How do you find the critical angle?

Answer 11

SinC=1/n then inverse sin

Question 12

What can be said about the refractive index moving from one medium to the other?

Answer 12

The index moving from denser medium to a less dense medium will have an index smaller than one

Question 13

How are phase differences represented?

Answer 13

Using radians

Question 14

What are phase differences used for?

Answer 14

To find superpositions

Question 15

What is the frequency of the 1st harmonic/fundamental frequency?

Answer 15

F=V/2L , where 2L can also be Lambda

Question 16

How does an open pipe affect the harmonics?

Answer 16

Both ends have antinodes, but it doesn’t affect the harmonics

Question 17

How does a closed pipe affect the harmonics?

Answer 17

The closed end has a node and the open end has an antinode causing the first harmonic to equal F=V/4L

Question 18

What is a photon?

Answer 18

Quantum of energy

Question 19

What is the model answer for spectrum?

Answer 19

1. Ground state electron
2. Photon absorbed causing movement to the cited state, which is unstable
3. De-excites with emission of a photon
4. frequency of the photon determines the wave type

Question 20

What is the definition of an Electronvolt?

Answer 20

The energy gained by an electron as it passes a potential difference

Question 21

How much energy is one Electronvolt?

Answer 21

1eV=1.6x10^-19

Question 22

What is the work function?

Answer 22

The minimum engird required to release a photoelectron

Question 23

What is the model answer for the photoelectric effect?

Answer 23

1. An electron is emitted from a photosensitive material on the basis of two factors
2. The photon must be above the threshold frequency
3. The photon must has the work function
4. Once these were reached the number of photoelectrons released depends upon the intensity of the light
5. 1 photon = 1 photoelectron

Question 24

What can be used to show the photoelectric effect?

Answer 24

The gold leaf experiment

Question 25

What happens in the gold leaf experiment?

Answer 25

1. There is a piece of gold leaf attached to a piece of metal within a vacuum, (a gold leaf electroscope)
2. A charged rod is then place on top of the Zinc plate on top of the electroscope
3. This charged rod causes a negative charge that then repels the piece of gold leaf from the zinc plating
4. When red light was shone on the plate nothing happened
5. when small amounts of UV light was shone on the plate, the leaf deceased in angle
6. This showed that the repulsion between metals was reducing and hence the charge