Unit 3.6 Nuclear Energy

Question 1

I mean if u wanna know, basically Einstein and how he formed this “so-called” formula.

Answer 1

• He was in a train
• Clock far away
• Speed
• Clock slow down far away
• Interesting…

Or just look in the booklet, but do u want to bet u’d do that?

Question 2

What is the formula Einstein formulated?
(The most famous equation)

Answer 2

E = mc²

Question 3

Define E
(Most famous equation)

Answer 3

Energy
(J)

Question 4

Define m
(Most famous equation)

Answer 4

Mass
(kg)

Question 5

Define c
(MOST² famous equation)

Answer 5

Speed of light
(ms^-1)

Question 6

What was the 1st proposal of Einstein’s equation?

Answer 6

1. An object at rest has a rest mass and therefore an intrinsic energy. This means that it’s mass and energy are equivalent.

Up to u if u wanna properly separate

Question 7

What was the 2nd proposal of Einstein’s equation?

Answer 7

2. As a particle gains velocity and therefore kinetic energy, its mass increases

Question 8

Hence, how can Einstein’s famous equation be rewritten, due to the 2 proposals?

Answer 8

△E = △mc²

Question 9

Define eV aka electron volt?
IMP

Answer 9

• Energy required to move…
• 1 electron through a pd of 1v

Question 10

1 eV = ?
(In data booklet)

Answer 10

1.6 x 10^-19J

Question 11

Describe & define ‘u’?

Answer 11

• Mass of a proton/neutron
• Equivalent to 1/12 of a carbon atom

Question 12

1u = ?
(In data booklet)

Answer 12

1.66 x 10^-27kg

Question 13

However, what’s 1u in MeV?
(+ a guide)

Answer 13

= 931/933
(generally, just use what it tells u in the question tho)

Question 14

What is the concept of binding energy and energy wells extremely useful in explaining?
(2-way)

Answer 14

• The stability o systems which are
• subject to attractive forces

Question 15

Magnets lumped together, spending time separating magnets.
Discuss work done in separating magnets?
(2 things)

Answer 15

• Work is done to separate magnets
• Energy transferred to the magnets

Question 16

Nuclear physicist separating nucleons from nucleus.
Discuss work done in separating nucleons?
(2 things)

Answer 16

• Work is done to separate the nucleons
• Energy transferred to the nucleons

Question 17

In other words, how do u separate nucleons so that they’re unbound work must be dine in each individual nucleon?
(2-way + 1)

Answer 17

• Work done is against the strong force
• of attraction acting between the nucleons
• Hence, nucleons must gain energy = work done

Question 18

Define binding energy [of a nucleus]?
(1-()-2-way)

Answer 18

• The work done
• (against the strong nuclear force)
• in separating the nucleus
• into its constituent particles

Question 19

How is the mass of the individual nucleons greater than the mass of the nucleus?
(3-way)

Answer 19

• Due to Einstein’s mass-energy equivalence:
• if they gain energy they must…
• appear to gain mass

Question 20

Well then what happens if nucleons are “allowed” to form a nucleus?
(2-way-no-biggie)

Answer 20

• First, in practise not easily done.
• Just mass loss

Question 21

What is the mass gain/loss between individual nucleons & nucleus’ sometimes referred to as?

Answer 21

Mass defect

Question 22

Equation for mass defect?
(NOT IN DATA BOOKLET)
(Oh and a tip)

Answer 22

Mass defect (Kg) = Total mass of individual nucleons (Kg) - Mass of nucleus (Kg)
- Always bigger one minus other
- Answer never negative

Question 23

So then, how do u get the binding energy of a nucleus?
(2 THINGS)

Answer 23

• Equation for mass defect
• Convert into Joules (x933/931)

Question 24

How do u get 1u = 931/933MeV?
(4 simple steps… actually 3)

Answer 24

• E = mc²
• (1.66x10^-27) x (3x10⁸)² = 1.40x10^-10
• 1.49x10^-10/(1.6x10^-19 x 1x10⁶)
• = 933 MeV

Question 25

How to find number of protons and electrons in an atom from periodic table?

Answer 25

Atomic number

Question 26

How to find number of neutrons in an atom from periodic table?

Answer 26

Mass number - atomic number

Question 27

Hence, in a decay eqn, how do u find the binding energy? e.g. **4**¹H₁ -> ⁴He₂ H = 1.007825u, He = 4.002604u (4-way)

Answer 27

- U given the masses of the following... - **1u = 933MeV as well too** - 4.0313 (<- x 4) - 4.002604 = 0.02896u - ans x 933 = THE ANSWER

Question 28

Find binding energy for this one: ²¹⁰Po_{84 -> ²⁰⁶Pb82 + ⁴He2 Po = 209.93667u, Pb = 205.92936u, He = 4.00150u}

Answer 28

- 209.93667 - (205.92936 + 4.00150) (= 209.93086) - = 5.81 x 10^-3u - (5.81x10^-3) x 931 - = 5.40911MeV

Question 29

Binding energy per nucleon = ?

Answer 29

Binding energy/n° of nucleons

Question 30

Relation between binding energy per nucleon and stability of nucleus? (2-way + 1 thing)

Answer 30

- The higher the binding energy per nucleon - the greater the stability of the nucleus - More energy needed to pull it apart

Question 31

There's more to come

Answer 31

But it's better if u start revisin' tho