9A.3 Fission And Fusion

Question 1

what is the mass deficit/defect

Answer 1

the difference between the measured mass of the nucleus and the sum total of the constituent nucleons

Question 2

what is biding energy

Answer 2

the energy used to hole the nucleus together, and its converted from the mass deficit following E = mc^2, alternatively it is the energy needed to break the nucleus into induvial nucleons

Question 3

why is the measured mass less than the constituent mass

Answer 3

because some of the constituent mass is converted into energy that is used to bind the nucleons in the nucleus

Question 4

how can we convert the mass deficit into Energy when its in u

Answer 4

1 u = 931.5 Mev

Question 5

when doing binding energy calculations always

Answer 5

use the largest S.F

Question 6

how do you find out the amount of energy required to remove one nucleon from a nucleus

Answer 6

find the binding energy of that nucleus then divide by the number of nucleons (this can be used to compare how strongly different nuclei’s are held together)

Question 7

any nuclear reaction with increasing binding energy per nucleon will

Answer 7

give out energy

Question 8

what is the element with the highest binding energy per nucleon

Answer 8

56 - iron

Question 9

what is fusion

Answer 9

small nuclides combine together to make larger nuclei, releasing energy

Question 10

what is fission

Answer 10

a large nuclei is broken into smaller nuclides, releasing energy

Question 11

past Iron 56 which nuclear reaction is more beneficial and why

Answer 11

nuclear fission since iron 56 has the highest binding energy per nuclei so when nuclei larger than iron - 56 are broken into smaller ones the nuclei made would have a larger binding energy so energy will be given out

Question 12

before Iron 56 which nuclear reaction is more beneficial and why

Answer 12

nuclear fusion, since the biding energy increases up to iron 56 so when the fuse their product would have a larger binding energy per nucleon so more energy is given out

Question 13

what are the stages of nuclear fusion

Answer 13

stage 1: two protons fuse

stage 2: one proton changes into a neutron by beta plus decay leaving a deuterium nucleus

stage 3: a proton join the deuterium nucleus to form He - 3

stage 4: two He -3 fuse

stage 5: two protons break off forming a He-4

Question 14

the energy released when a nucleus with a bigger binding energy per nucleon is made from two smaller nuclei comes from

Answer 14

the mass deficit, but most of the mass deficit is used for binding energy

Question 15

why cant we currently use nuclear fusion to supply energy on earth

Answer 15

1. very high energy are required to make two positively charged protons to collide
2. very large density of protons to ensure that each colliding proton in the reaction is sustained
3. it needs very strong magnetic fields

Question 16

why is nuclear fusion a smart way to get energy:

Answer 16

1. we can find hydrogen in water molecules (abundant)
2. Helium produced is an inert gas and is safe to stay in our atmosphere

Question 17

what is nuclear fission

Answer 17

a large nucleus breaks into two smaller nuclei, with the release of some neutrons and energy

Question 18

when does nuclear fission occur

Answer 18

when a nucleus absorbs another particle (usually a neutron) which makes it unstable

Question 19

why is using U-235 hard

Answer 19

because U-235 is a small portion of uranium and we need a lot of Uranium fuel to provide enough U-235 to produce large energies