Quantum Phenomena Definitions

Question 1

Work Function

Answer 1

MINIMUM ENERGY needed to remove an electron from the SURFACE of a material

Question 2

Work Function Units

Answer 2

joules

Question 3

Threshold Frequency

Answer 3

MINIMUM FREQUENCY needed to remove an electron from the SURFACE of a metal

Question 4

hf

Answer 4

photon energy

Question 5

Φ

Answer 5

work function

Question 6

Ek(max)

Answer 6

maximum kinetic energy of the released photoelectron

Question 7

Electron Volt eV

Answer 7

the energy gained 1eV by an electron moved across a potential difference of 1V

Question 8

Converting between eV and J

Answer 8

1eV=1.6x10^-19J

Question 9

Excitation

Answer 9

An orbital electron moving up one energy level to another

Question 10

Excited Atom

Answer 10

Atom in which an orbiting electron is raised up to a higher energy level

Question 11

Ionisation (gas discharge tube)

Answer 11

when an electron is removed from an atom

Question 12

Ionisation Energy

Answer 12

energy required to completely remove an electron from an atom in its ground state

Question 13

Ground state of an atom

Answer 13

the lowest energy state of an atom

Question 14

Fluorescence

Answer 14

high energy (UV) photons are absorbed and lower energy photons (with a longer wavelength) are emitted in the visible part of the spectrum

Question 15

Wave Particle Duality

Answer 15

particles (photons, light) behave sometimes as particles and waves

Question 16

Experiment showing waves behaving as particles

Answer 16

Photoelectric Effect

Question 17

Experiment showing particles behaving as waves

Answer 17

Electron Diffraction

Question 18

Momentum (p)

Answer 18

mass x velocity (p=mv)

Question 19

Units of momentum

Answer 19

kg ms^-1

Question 20

Stopping Potential

Answer 20

the potential difference needed to stop the fastest moving photoelectrons travelling with kinetic energy in the photoelectron effect

Ekmax= e x Vstopping

Question 21

Particle Diffraction Effects

Answer 21

A particle will diffract when the sizeof the de Broglie wavelength is roughly the same size as the object causing the diffraction