2.5 Quantum Physics

Question 1

Photon

Answer 1

‘An indivisible packet of electromagnetic energy’

Question 2

Quantised

Answer 2

‘Specific/whole integer number’

Question 3

Electron volt, eV

Answer 3

‘The energy possessed by an electron which has been accelerated through a pd of 1V’

Question 4

Work function

Answer 4

‘Minimum energy required to release and electron from the surface of a metal’

Question 5

Threshold frequency

Answer 5

‘Minimum frequency a photon requires to release a photoelectron from a metal surface’

Question 6

Ground state

Answer 6

‘Lowest possible energy level/stable level’

Question 7

Energy level

Answer 7

‘an orbit with an energy where an electron can remain’

Question 8

LASER

Answer 8

‘Light Amplification by the Stimulated Emission of Radiation’

Question 9

Collimated

Answer 9

‘All parts travel in the same direction’

Question 10

Population inversion

Answer 10

‘Achieving more electrons in an excited state than in the ground state’

Question 11

Metastable state

Answer 11

‘An energy Level where an electron is stable for several magnitudes of time longer than a normal energy level’

Question 12

Spontaneous emission

Answer 12

‘The spontaneous falling of an electron from a high to low energy level, with the emission of energy E2-E1 in a random direction’

Question 13

Stimulated emission

Answer 13

‘A passing photon of the exact required energy causes an electron to fall from a high to low energy level. The falling electron emits a photon of the same energy and direction as the stimulating photon and has a constant phase difference’

Question 14

CT

Answer 14

Computed tomography

Question 15

Photon equations and planks constant value

Answer 15

E=hf or E=hc/¥
h=6.63x10^-34

Question 16

EV equation and value

Answer 16

E=VQ
1eV=1.6x10^-19

Question 17

Excitation causes

Answer 17

1. Electron collision; -ionisation-excitation
2. Incoming photon- must exactly equal difference between two levels

Question 18

Relaxation explanation

Answer 18

-The electron configuration in an excited atom is unstable because a vacancy is left in the shell it moved from
-sooner or later, the vacancy is filled by an electron from an outer shell transferring to it. When this happens, the electron emits and photon
-the energy level of the photon js equal to the energy lost by the electron and therefore by the atom