QUANTUM

Question 1

what is the eV

Answer 1

is the energy gained by an electron, accelerated by a pd of 1v

Question 2

how do you convert from V to eV ?

Answer 2

multiply by 1.6x10^-19

Question 3

what is the relationship between the frequency of a particle and the frequency of the wave

Answer 3

E=hf

Question 4

what is planck’s constant

Answer 4

6.63x10^-34

Question 5

what is the threshold voltage?

Answer 5

a value below which a no current will flow through the diode

Question 6

what is the wavelength of red light?

Answer 6

700 nanometers

Question 7

what is the wavelength of blue light?

Answer 7

450 nanometers

Question 8

what is the wavelength of green light?

Answer 8

550 nanometers

Question 9

what will the gradient be on a V over 1/λ graph?

Answer 9

Vλ or hc/e

since
e=hf=hc/λ
e=eV
eV=hc/λ
vλ =hc/e

Question 10

what is the photoelectric effect

Answer 10

when electromagnetic radiation of a particular frequency is shone on the surface of a meal, electrons are emitted from its surface.

Question 11

what is the work function

Answer 11

Is the minimum energy required to release an electron from the surface, overcoming the electrostatic attraction between the electron and the positive metal ions.

Question 12

what is the energy of a photon directly proportional to ?

Answer 12

The frequency.

E=hf

Question 13

what is the work function

Answer 13

the minimum energy required to release a delocalised electron from the surface of the metal

Question 14

what happens when the energy of the photon is equal to the work function

Answer 14

we get the threshold frequency

Question 15

what is the threshold frequency

Answer 15

minimum frequency required to release the delocalised electron from the surface

Question 16

what happens if the incident photon has more than the threshold frequency

Answer 16

there will be energy left over, this will be the kinetic energy of the electron.

Question 17

if an electron is emitted in an electric field, what direction will in go in relation to the field lines

Answer 17

opposite, it will take a parabolic motion, forming a current as long as it reachers the other plate.

Question 18

how do you calculate the work done moving an electron across a potential difference?

Answer 18

W=eV, charge of electron, by the potential difference.

Question 19

what is stopping potential?

Answer 19

where the Ek, is equal to the charge x the pd, we call this pd the stopping pd. any pd greater will stop the current.

Question 20

how do you calculate stopping potential

Answer 20

hf=Ø+Vs

Question 21

what are energy levels

Answer 21

these are the levels in which electrons can orbit a nucleus. they go from 1 to infinity hypothetically

Question 22

what causes electrons to move energy levels

Answer 22

photons, heat…

Question 23

what happens to the energy stored in an electron when it moves up an energy level

Answer 23

it loses energy as a photon of radiation.