Energy and mass

Question 1

What did einstein show about the mass of the object>

Answer 1

• as energy increases, mass increases

Question 2

How does annihilation and production prove E = mc²?

Answer 2

• when annihiliate, 2 gamma photons releases, energy = to mc²

Question 3

What happens to mass during decay?

Answer 3

• total mass after the change is always lesss than the total mass befopre the change
• some mass convetrted to energy which is released

Question 4

What is the binding energy of the nucleus?

Answer 4

• work that must be done to separate a nucleus into its consitituent neutrons and protons
• binding energy = energy released when pulling nucleons

Question 5

What is the mass defect ?

Answer 5

• mass defect of a nucleus is defined as the difference between the mass of the separated nucleons and mass of nucleus

Question 6

What is the binding energy per nucleon?

Answer 6

• binding energy per nucleon of a nucleus is the average work done per nucleon to remove all the nucleons from a nucleus
• therefore a measure of the stability of the nucleus

Question 7

What is nuclear fission?

Answer 7

• process in which a large unstable nucleus splits into two fragments which are more stable than the original nucleus
• the binding energy per nucleon increases in this process

Question 8

What is nuclear fusion?

Answer 8

• process of making small nulei fuse together to form a larger nucleus
• the product nucleus has more binding energy per nucleon than the smaller nuclei
• so the binding energy per nucleon aslo increases in the process
• provided the number of the product nucleus is no more than about 50