Exam 3 Review Key
Exam Objectives
Describe the difference between fusion and fission
Describe alpha, beta, and gamma emissions
Define half life
Perform half life equations
Fill in missing information for nuclear equations
Write nuclear equations when given an element and the type of decay in undergoes
Review Key
What process powers the sun?
Fission
Fusion (correct)
Gamma decay
Electron capture
What process occurs in nuclear power plants?
Fusion
Positron emission
Fission (correct)
Alpha decay
True or False: Fusion joins two light nuclei into one heavier nucleus.
True (correct)
False
True or False: Fission splits a nucleus into smaller parts.
True (correct)
False
Alpha particles have:
2 protons and 2 neutrons (correct)
1 neutron and 1 proton
2 electrons
No charge
Beta particles are:
High-energy helium nuclei
High-energy electrons (correct)
Neutrons
Gamma rays
Gamma radiation is:
Made of particles
Stopped by paper
Electromagnetic waves (correct)
Positively charged
True or False: Gamma rays have the lowest penetrating power
True
False (correct)
What particle has no mass and no charge?
Proton
Neutron
Alpha
Photon (correct)
True or False: Beta radiation is stopped by paper.
True
False (correct)
All of the following describe alpha particles EXCEPT:
Heaviest radiation
Stopped by paper
Made of helium nuclei
Have a negative charge (correct)
All of the following describe beta emission EXCEPT:
Releases high-energy electrons
Stopped by metal
Releases gamma rays (correct)
Involves a neutron turning into a proton
All of the following are characteristics of gamma rays EXCEPT:
No mass
Most penetrating
Particles with charge (correct)
Often emitted with alpha or beta decay
What is the key difference between beta emission and positron emission?
Beta emits a proton; positron emits an electron
Beta releases a negative particle; positron releases a positive one. (correct)
Beta is not a nuclear process
Positron has more mass
What’s the key difference between beta emission and electron capture?
Beta adds electrons; electron capture releases them
Beta happens inside the nucleus; electron capture does not
Beta releases an electron; electron capture absorbs one (correct)
Electron capture emits photons
Half-life is defined as:
Time it takes to stop a reaction
Time it takes for all nuclei to decay
Total time a nucleus remains stable
Time it takes for half of a radioactive sample to decay (correct)
True or False: A longer half-life means a faster decay rate.
True
False (correct)
In a half-life problem, the amount left is called:
Initial quantity
Remaining quantity (correct)
Full mass
Time passed
Which pair is correctly matched?
Alpha — high penetrating power
Beta — helium nucleus
Gamma — electromagnetic wave (correct)
Positron — negative electron
Which shows beta emission?
\frac{14}{6}C\to\frac{14}{7}N+\frac{0}{-1}e (correct)
\frac{238}{92}U\to\frac{234}{90}Th+\frac42He
\frac{60}{27}Co^{\ast}\to\frac{60}{27}Co+\frac00\gamma
\frac{11}{6}C+\frac{0}{-1}e\to\frac{11}{5}B
What completes this nuclear equation for beta decay: \frac{14}{6}C\to?+\frac{0}{-1}e
\frac{14}{5}B
\frac{14}{7}N (correct)
\frac{12}{6}C
\frac{15}{7}N
What completes this nuclear equation for alpha decay: \frac{238}{92}U\to?+\frac42He
\frac{234}{90}Th (correct)
\frac{236}{91}Pa
\frac{238}{91}Pa
\frac{240}{94}Pu
Which shows alpha emission?
\frac{14}{6}C\to\frac{14}{7}N+\frac{0}{-1}e
\frac{238}{92}U\to\frac{234}{90}Th+\frac42He (correct)
\frac{60}{27}Co^{\ast}\to\frac{60}{27}Co+\frac00\gamma
\frac{11}{6}C+\frac{0}{-1}e\to\frac{11}{5}B
Which shows gamma emission?
\frac{14}{6}C\to\frac{14}{7}N+\frac{0}{-1}e
\frac{238}{92}U\to\frac{234}{90}Th+\frac42He
\frac{60}{27}Co^{\ast}\to\frac{60}{27}Co+\frac00\gamma (correct)
\frac{11}{6}C+\frac{0}{-1}e\to\frac{11}{5}B
What completes this nuclear equation for gamma decay: \frac{60}{27}Co^{\ast}\to?+\frac00\gamma
\frac{60}{27}Co^{\ast} (correct)
\frac{60}{26}Fe^{\ast}
\frac{60}{28}Ni^{\ast}
\frac{59}{27}Co^{\ast}