quantum (photoelectric effect)

Question 1

relationship between two properties of a photon

Answer 1

energy is directly proportional to the frequency

Question 2

what is a photon

Answer 2

packets of energy

Question 3

what is annihilation

Answer 3

when a particle and its antiparticle collide and they become pure energy-producing two gamma photons

Question 4

how much energy do the gamma photons from annihilation have

Answer 4

it must be equal to the total energy of the particles (rest mass energy + kinetic energy). this means each photon has a minimum of the rest mass energy of one particle

Question 5

what is pair production?

Answer 5

when one high energy photon turns into a particle-antiparticle pair

Question 6

how much energy does the photon need for pair production

Answer 6

at least the rest mass energy of the particle-antiparticle pair

Question 7

what is a threshold frequency

Answer 7

the minimum frequency of light for an electron to be removed from the surface of a metal

Question 8

what affects the energy of the electron released

Answer 8

its kinetic energy is dependent on the frequency of the light

Question 9

what affects the number of electrons released

Answer 9

the number released is directly proportional to the intensity of the light

Question 10

why does wave theory fail to explain the photoelectric effect

Answer 10

wave theory states that the intensity should determine the energy transferred to electrons per second so we would expect intensity and the kinetic energy of the electrons to be proportional

Question 11

how did einstein explain the photoelectric effect

Answer 11

he stated that light is made of photons and each electron only interacts with one photon. since intensity is the number of photons arriving per second this explained why intensity is proportional to the number released

Question 12

what did einstein suggest about photons

Answer 12

their energy is proportional to the frequency which explains why the kinetic energy of the electrons is dependant on the frequency

Question 13

define the work function

Answer 13

the minimum energy required to remove an electron from the surface of a metal

Question 14

proof that light is a wave or a particle

Answer 14

wave- diffraction, interference

particle- photoelectric effect

Question 15

what did de Broglie suggest

Answer 15

any particle with momentum had a wavelength

Question 16

how was de Broglie’s theory proven

Answer 16

experiments showed that electrons can diffract through a grating. and had a wavelength equal to what he suggested

Question 17

how can we observe diffraction in electrons?

Answer 17

they can have their wavelength reduced the distance between atoms in a crystal and then be diffracted through it

Question 18

what is the photoelectric effect

Answer 18

when a photon of light is absorbed by an electron at the surface of a metal and is released