PHB - Term 4 (E1, E3)

Question 1

Define Isotope

Answer 1

Nuclei that have the same number of protons but different numbers of neutrons

Question 2

Define Binding Energy

Answer 2

The energy required to break a nucleus into its constituent protons and neutrons

Question 3

Define Half-Life

Answer 3

The time taken for half the undecayed nuclei to decay or the activity of a source to decay by half

Question 4

Thomson Model

Answer 4

Also known as the plum pudding model of the atom. Positive charge (dough) with negative electrons

Question 5

Geiger-Marsden-Rutherford experiment

Answer 5

Alpha particles fired at a thin sheet of gold foil. Discovered the existence of the nucleus, small, dense, positive

Question 6

eV to J

Answer 6

1eV to 1.6x10^-19 J

Question 7

Change in energy in Atomic Transitions

Answer 7

ΔE = Ei - Ef

Question 8

Define eV

Answer 8

The kinetic energy an electron gains when it accelerated across a potential difference of 1V

Question 9

Discrete emission spectrum

Answer 9

Because energy levels are discrete, photons emitted by gases only have discrete energies equal to the differences between atomic energy levels. E=hc/λ

Question 10

Define Photons

Answer 10

‘Packets’ of electromagnetic energy, discrete quantity

Question 11

What does the frequency in E=hf show

Answer 11

The frequency of photons emitted when de-excitation occurs

Question 12

Atomic Transitions in relation to the light spectrum

Answer 12

n=x -> n=1 is ultraviolet || n=x -> n=2 is visible light || n=x -> n=3 is infrared

Question 13

The emission spectrum

Answer 13

Hydrogen gas is excited it will emit photons with specific energies/wavelengths. Consists of bright emission lines on dark backgrounds

Question 14

The absorption spectrum

Answer 14

Shine a white light on hydrogen gas, absorbs the photons with energies that correspond to the possible atomic transitions. Consists of dark lines on a bright bg

Question 15

What is Background Radiation

Answer 15

The ionising radiation present in the environemtn

Question 16

Alpha Decay (4)

Answer 16

(4,2)α || High energy helium nucleus || emitted by Large unstable nucleus || Highly ionising, least penetrating

Question 17

Beta-Minus Decay (4)

Answer 17

(0,-1) β || High energy electron || emitted by unstable nuclei with too many neutrons || Neutrons turn into a proton with an anti neutrino

Question 18

Beta-Plus Decay (4)

Answer 18

(0,+1) β || High energy positron || emitted by unstable nuclei with too many protons || Proton turns into neutron with a positive neutrino

Question 19

Gamma Radiation (4)

Answer 19

(0,0)γ || High energy electromagnetic radiation || Emitted by nuclei that need to lose energy || Weakly ionising and highest penetrating

Question 20

Ionisation

Answer 20

Damages or Destroys Cells, increased exposure may cause illness or death

Question 21

Mass-Energy equivalence

Answer 21

E = mc^2
m = mass defect (kg)

Question 22

u –> kg

Answer 22

1u = 1.661x10^-27 kg

Question 23

Define Mass Defect

Answer 23

m = Total mass of individual nucleons(u) - mass of nucleus

Question 24

Strong force range

Answer 24

Strong Force < 0.5 fm ==> Repulsive
0.5 < Strong Force < 3 ==> Attractive
0.5 = Equilibrium