Define mass-energy equivalence .

Mass-energy equivalence is Einstein's principle that mass can be converted into energy, and energy can be converted into mass.

Give examples of processes where mass-energy equivalence applies.

The fusion of hydrogen into helium in the centre of the Sun The fission of uranium in nuclear power plants Nuclear weapons High-energy particle collisions in particle accelerators

Mass-energy equivalence states that mass can be converted into .......... , and energy can be converted into mass.

Mass-energy equivalence states that mass can be converted into energy , and energy can be converted into mass.

Define nucleon number ( A ).

Nucleon number ( A ) is the total number of protons and neutrons in a nucleus.

Define proton number ( Z ).

Proton number ( Z ) is the total number of protons in a nucleus.

What two quantities must balance on both sides of a nuclear equation?

Nucleon number ( A ) Proton number ( Z )

True or False? In a nuclear equation, the nucleon numbers on each side must balance, but the proton numbers do not need to.

False. Both the nucleon number ( A ) and the proton number ( Z ) must balance on each side of a nuclear equation.

Mass defect is the difference between the mass of a nucleus and the sum of the individual masses of its protons and neutrons.

Define binding energy .

Binding energy is the energy required to break a nucleus into its constituent protons and neutrons.

Define binding energy per nucleon .

Binding energy per nucleon is the binding energy of a nucleus divided by the number of nucleons in the nucleus.

Why do helium-4, carbon-12 and oxygen-16 not fit the general trend on the binding energy per nucleon graph?

They have unusually high binding energy per nucleon for their mass; carbon-12 and oxygen-16 can be considered as three and four helium-4 nuclei bound together, and helium-4 is itself a particularly stable nucleus.

On the graph of binding energy per nucleon against nucleon number, the gradient at low values of A is .......... than the gradient at high values of A .

On the graph of binding energy per nucleon against nucleon number, the gradient at low values of A is steeper than the gradient at high values of A .

True or False? Binding energy is the energy stored inside a nucleus.

False. Binding energy is the energy that must be put into the nucleus to separate all of its nucleons — it is not energy stored within the nucleus.

Define nuclear fusion .

Nuclear fusion is when two nuclei combine to form a single nucleus.

Define nuclear fission .

Nuclear fission is when a single large nucleus divides to form smaller nuclei.

Why must colliding nuclei have high kinetic energy in order to fuse?

Protons are positively charged and electrostatically repel one another The strong nuclear force that binds nucleons acts only over very short distances, so nuclei must get very close together for it to take effect Overcoming the repulsion requires an extremely hot environment, such as the core of a star

What happens during induced nuclear fission when a neutron strikes a target nucleus?

The nucleus splits into two or more daughter nuclei and ejects further neutrons, which can strike other nuclei and trigger a chain reaction .

What happens if a fission chain reaction is not carefully controlled?

It cascades uncontrolled, producing the effects of a nuclear bomb, rather than the controlled energy release used in nuclear power stations.

Why do low nucleon number ( A ) nuclei tend to undergo fusion rather than fission?

At low A , the attractive strong nuclear force between nucleons dominates over the repulsive electrostatic forces between protons, so fusion is favoured; the nucleus formed has slightly less mass than the original nuclei, releasing the mass defect as binding energy.

Why do high nucleon number ( A ) nuclei tend to undergo fission rather than fusion?

At high A , repulsive electrostatic forces between protons dominate and tend to break the nucleus apart; fission converts an unstable nucleus into more stable nuclei with a smaller total mass, releasing the mass defect as binding energy.

In deuterium-tritium fusion, a deuterium nucleus and a tritium nucleus fuse to produce a helium nucleus and a .......... .

In deuterium-tritium fusion, a deuterium nucleus and a tritium nucleus fuse to produce a helium nucleus and a neutron .

True or False? In nuclear fission, the extra neutrons are ejected from the fission product nuclei, not from the original target nucleus.

False. The extra neutrons are ejected from the original nucleus as it splits, not from the fission products.

Define binding energy .

Binding energy is the energy released when a nucleus is formed from its constituent nucleons.

Why is energy released in both nuclear fission and nuclear fusion reactions?

The daughter nuclei have a higher binding energy per nucleon than the parent nuclei , so energy is released due to the mass difference between them.

How can the total binding energy of a nucleus be calculated from its binding energy per nucleon?

Total binding energy = binding energy per nucleon × mass number ( A )

In both fission and fusion, the daughter nuclei have a .......... binding energy per nucleon than the parent nuclei.

In both fission and fusion, the daughter nuclei have a higher binding energy per nucleon than the parent nuclei.

True or False? In nuclear fission, the parent nucleus has a higher binding energy per nucleon than the daughter nuclei.

False. The daughter nuclei have a higher binding energy per nucleon than the parent nucleus; this difference in binding energy is released as energy.

A LevelPhysicsCambridge (CIE)Flashcards23. Nuclear PhysicsMass Defect & Nuclear Binding Energy

Mass Defect & Nuclear Binding Energy (Cambridge (CIE) A Level Physics): Flashcards

Exam code: 9702

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FrontEnergy & Mass Equivalence
Define mass-energy equivalence.
FrontEnergy & Mass Equivalence
State the mass-energy equivalence equation, including the units of each term.
BackEnergy & Mass Equivalence
$E = m c^{2}$
E = energy (J)
m = mass (kg)
c = speed of light (m s^-1)
FrontEnergy & Mass Equivalence
Give examples of processes where mass-energy equivalence applies.
BackEnergy & Mass Equivalence
The fusion of hydrogen into helium in the centre of the Sun
The fission of uranium in nuclear power plants
Nuclear weapons
High-energy particle collisions in particle accelerators

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Cards in this collection (34)

Define mass-energy equivalence.
Mass-energy equivalence is Einstein's principle that mass can be converted into energy, and energy can be converted into mass.
State the mass-energy equivalence equation, including the units of each term.
$E = m c^{2}$
- E = energy (J)
- m = mass (kg)
- c = speed of light (m s^-1)
Give examples of processes where mass-energy equivalence applies.
- The fusion of hydrogen into helium in the centre of the Sun
- The fission of uranium in nuclear power plants
- Nuclear weapons
- High-energy particle collisions in particle accelerators
Mass-energy equivalence states that mass can be converted into .........., and energy can be converted into mass.
Mass-energy equivalence states that mass can be converted into energy, and energy can be converted into mass.
True or False?
Mass and energy are each independently conserved in every physical process.
False.
Einstein's mass-energy equivalence ( $E = m c^{2}$ ) shows mass and energy are interconvertible, so it is the total mass-energy that is conserved, not mass and energy separately.
Define nucleon number (A).
Nucleon number (A) is the total number of protons and neutrons in a nucleus.
Define proton number (Z).
Proton number (Z) is the total number of protons in a nucleus.
What two quantities must balance on both sides of a nuclear equation?
- Nucleon number (A)
- Proton number (Z)
In ${}_{Z}^{A}X$ notation, the lower number Z represents the .......... number.
In ${}_{Z}^{A}X$ notation, the lower number Z represents the proton number.
True or False?
In a nuclear equation, the nucleon numbers on each side must balance, but the proton numbers do not need to.
False.
Both the nucleon number (A) and the proton number (Z) must balance on each side of a nuclear equation.
When a neutron is captured by uranium-235, the reaction is represented by:
${}_{92}^{235}U +_{0}^{1} n \to_{42}^{95} M o +_{57}^{139} L a + x_{0}^{1} n + 7_{- 1}^{0} e$
Determine the value of x.
Balancing nucleon numbers: 235 + 1 = 95 + 139 + x(1) + 7(0)
x = 235 + 1 − 95 − 139 = 2
Define mass defect.
Mass defect is the difference between the mass of a nucleus and the sum of the individual masses of its protons and neutrons.
Define binding energy.
Binding energy is the energy required to break a nucleus into its constituent protons and neutrons.
State the equation linking binding energy to mass defect, including what each symbol represents.
$E = Δ m c^{2}$
- E = binding energy (J)
- Δm = mass defect (kg)
- c = speed of light (m s^-1)
Define binding energy per nucleon.
Binding energy per nucleon is the binding energy of a nucleus divided by the number of nucleons in the nucleus.
Which nuclide has the highest binding energy per nucleon, making it the most stable?
Iron-56 ( ${}_{26}^{56}F e$ ), at nucleon number A = 56.
Why do helium-4, carbon-12 and oxygen-16 not fit the general trend on the binding energy per nucleon graph?
They have unusually high binding energy per nucleon for their mass; carbon-12 and oxygen-16 can be considered as three and four helium-4 nuclei bound together, and helium-4 is itself a particularly stable nucleus.
On the graph of binding energy per nucleon against nucleon number, the gradient at low values of A is .......... than the gradient at high values of A.
On the graph of binding energy per nucleon against nucleon number, the gradient at low values of A is steeper than the gradient at high values of A.
True or False?
Binding energy is the energy stored inside a nucleus.
False.
Binding energy is the energy that must be put into the nucleus to separate all of its nucleons — it is not energy stored within the nucleus.
Define nuclear fusion.
Nuclear fusion is when two nuclei combine to form a single nucleus.
Define nuclear fission.
Nuclear fission is when a single large nucleus divides to form smaller nuclei.
Why must colliding nuclei have high kinetic energy in order to fuse?
- Protons are positively charged and electrostatically repel one another
- The strong nuclear force that binds nucleons acts only over very short distances, so nuclei must get very close together for it to take effect
- Overcoming the repulsion requires an extremely hot environment, such as the core of a star
What happens during induced nuclear fission when a neutron strikes a target nucleus?
The nucleus splits into two or more daughter nuclei and ejects further neutrons, which can strike other nuclei and trigger a chain reaction.
What happens if a fission chain reaction is not carefully controlled?
It cascades uncontrolled, producing the effects of a nuclear bomb, rather than the controlled energy release used in nuclear power stations.
Why do low nucleon number (A) nuclei tend to undergo fusion rather than fission?
At low A, the attractive strong nuclear force between nucleons dominates over the repulsive electrostatic forces between protons, so fusion is favoured; the nucleus formed has slightly less mass than the original nuclei, releasing the mass defect as binding energy.
Why do high nucleon number (A) nuclei tend to undergo fission rather than fusion?
At high A, repulsive electrostatic forces between protons dominate and tend to break the nucleus apart; fission converts an unstable nucleus into more stable nuclei with a smaller total mass, releasing the mass defect as binding energy.
In deuterium-tritium fusion, a deuterium nucleus and a tritium nucleus fuse to produce a helium nucleus and a ...........
In deuterium-tritium fusion, a deuterium nucleus and a tritium nucleus fuse to produce a helium nucleus and a neutron.
True or False?
In nuclear fission, the extra neutrons are ejected from the fission product nuclei, not from the original target nucleus.
False.
The extra neutrons are ejected from the original nucleus as it splits, not from the fission products.
Define binding energy.
Binding energy is the energy released when a nucleus is formed from its constituent nucleons.
What equation relates the energy released in a nuclear reaction to the mass defect?
$E = (Δ m) c^{2}$
where E is the energy released (J), Δm is the mass defect (kg) and c is the speed of light (m s^-1)
Why is energy released in both nuclear fission and nuclear fusion reactions?
The daughter nuclei have a higher binding energy per nucleon than the parent nuclei, so energy is released due to the mass difference between them.
How can the total binding energy of a nucleus be calculated from its binding energy per nucleon?
Total binding energy = binding energy per nucleon × mass number (A)
In both fission and fusion, the daughter nuclei have a .......... binding energy per nucleon than the parent nuclei.
In both fission and fusion, the daughter nuclei have a higher binding energy per nucleon than the parent nuclei.
True or False?
In nuclear fission, the parent nucleus has a higher binding energy per nucleon than the daughter nuclei.
False.
The daughter nuclei have a higher binding energy per nucleon than the parent nucleus; this difference in binding energy is released as energy.

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