Topic 4 - Waves

Question 1

simple harmonic motion ( 3 things )

Answer 1

• Force is restorative
• Repetitive motion
• acceleration is proportional to displacement, but in the opposite direction

Question 2

Phase Change

Answer 2

• radians
• cycles or fractions of period
• phi Φ

Question 3

What can you get from : x-t graph

Answer 3

• frequency
• amplitude
• wave height
• v-t graph
• period
• NO WAVELENGTH

Question 4

waves : mechanical (the types)

Answer 4

• needs a medium to travel (ie water or sound waves)

Transversal
* Particles move perpendicular to the propagation of energy

Longitudinal
* particles move parallel with the wave motion
* now there is rarefaction and compression present
* on x-t graph, peak is compression and valley is rarefraction

Question 5

waves : electromagnetic

Answer 5

• no medium needed
• electric field is normal to the magnetic field

Question 6

EMS Spectrium

Answer 6

wavelength
* violet -> Red
* violet = 400nm
*red = 700nm

Question 7

Intensity (Equations)

Answer 7

Question 8

Spherical Intensity (Equation)

Answer 8

Question 9

What can waves do

Answer 9

reflect
* wave meeting boundary, and at least partially diverted backwards

• refract / transmit
• interfere (superposition)
• diffraction (single + double slit)

Question 10

transmission / refraction (into more dense)

Answer 10

Question 11

transmission / refraction (into less dense)

Answer 11

Question 12

what it does: polarizer

Answer 12

• turns 360˚ light into planar (usually EMS light)
• turns I into 1/2 I

Question 13

what it does: analyzer

Answer 13

• this is the one at an angle to decrease intensity

Question 14

Malus’s Law

Answer 14

Question 15

Intensity due to Polarizer (Flip)

Answer 15

Question 16

Brewster’s Law

Answer 16

than the reflected light is plane-polorised

Question 17

Snell’s Law

Answer 17

n1 sinθ1 = n2 sinθ2

Question 18

Critical Angle

Answer 18

• no refraction
• all internal reflection

Question 19

diffraction (single slit)

Answer 19

if slit is smaller than wavelength, or object is larger than wavelength

Christian Huggens found it out

Question 20

Path Difference

Answer 20

If integer (x) path difference: maximum constructive interference

if x+0.5 path difference: maximum deconstructive

Question 21

where are nodes and anodes

Answer 21

Question 22

String Instrument

Answer 22

Closed Pipe

Question 23

Flute

Answer 23

Open Pipe

Question 24

Clarinet

Answer 24

one closed - one open