7.2 the nature of matter

Question 1

what is planck‘s constant

Answer 1

6.626 x 10 to the -34

Question 2

what is the formula relating placks constant and energy

Answer 2

delta E = nhv

n = integer
v = frequency of the electromagnetic radiation absorbed or emmited

energy can be lost for integer values of hv

Question 3

what is a photon

Answer 3

• a piece of enegie
• they are quantized, travel in discrete units, not long wavelenghts, discrete little particles
• they hAVE FIXED ENERGY, QUANTIZED
• not a particle, but acts like one
  = E photon = (h)(f)

Question 4

what are the main principles of the photoelectric effect?

Answer 4

When piece of metal is bombarded with electrons:
- no electrons are emited below a specific threshold frequency
- light with frequency lower than threshold frequency will not emmit electrons regardless of the intensity of the light
- for light greater than threshold, num of electrons emitied increases with intensity of the light
- kinetic energy of emited electrons also increases linearly with intensity of the light

Question 5

what is the nuane with the mass of a photon

Answer 5

Photon‘s do not actually have a mass, they have an apparent mass, can act as if they have a mass

Question 6

what is an interferrance pattern (diffraction)

Answer 6

when 2 disturbances occur near one another, and their respective series of waves overlap

Question 7

what is constructive interference

Answer 7

resulting wave is bigger than original waves

Question 8

what is destructive interference

Answer 8

resulting wave has an amplitude of 0

Question 9

for periodic waves how is there a constructive interference, what does it produce

Answer 9

when the waves of in phase, alined
produces a bright spot

Question 10

for periodic waves how is there a destructive interference, what does it produce

Answer 10

when the waves are out of phase, (the through of one wave is over the pick of the other) , produces a dark spot