Radius of a Gold Nucleus

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What is the approximate energy of an alpha particle in joules?

1.2 x 10^-12 J

What is the charge of a gold nucleus in terms of elementary charge?

+79e

What is the ratio of the radius of an atom to the radius of its nucleus?

10,000:1

What is the approximate mass of 100 nucleons in units of u?

100 u Signup and view all the answers

What is the relationship between the radius of a nucleus and its relative atomic mass A?

R = r0 A^(1/3) Signup and view all the answers

What is the value of the constant r0 in the relationship R = r0 A^(1/3)?

1.2 fm Signup and view all the answers

What is the unit of the nuclear density in SI units?

kg/m^3 Signup and view all the answers

How many fundamental forces are there in the universe?

4 Signup and view all the answers

What is the minimum energy required to create an electron-positron pair through pair production?

1.02 MeV Signup and view all the answers

What is the relationship between the mass of a particle and its antiparticle?

They always have the same mass Signup and view all the answers

What are the two main classes of fundamental particles?

Hadrons and leptons Signup and view all the answers

What are quarks typically found in?

Quark-antiquark pairs (mesons) or groups of three (baryons) Signup and view all the answers

What is the baryon number of protons and neutrons?

1 Signup and view all the answers

What is the characteristic of the charge of quarks?

Fractions of the elementary charge Signup and view all the answers

What is the name of the particles made up of quark-antiquark pairs?

Mesons Signup and view all the answers

What is the energy of a photon required to create a matter-anti matter pair?

Greater than the combined rest masses of the two particles Signup and view all the answers

What is the force responsible for the decay of hadrons?

The weak force Signup and view all the answers

Why are leptons not affected by the strong force?

Because they are fundamental particles that do not participate in the strong nuclear force Signup and view all the answers

What is the purpose of conserving lepton number in nuclear reactions?

To conserve the charge and mass-energy of the interaction Signup and view all the answers

What makes neutrinos difficult to detect?

Their very low mass and zero charge Signup and view all the answers

What is the characteristic of radioactive decay that makes it unpredictable?

It is a random process Signup and view all the answers

What is the significance of the half-life in radioactive decay?

It is the time taken on average for half of the active isotopes in a sample to decay Signup and view all the answers

What is the probability of none of the sample decaying in a given time?

Very small, but not zero Signup and view all the answers

What is the pattern of radioactive decay?

Each decay follows a defined pattern, but the timing is random Signup and view all the answers

What is the average time it takes for half of the sample to decay, and what is it represented by?

Half-life, represented by 𝑡𝑡1/2 Signup and view all the answers

What is the relationship between the decay constant and half-life?

𝜆𝜆𝑡𝑡1/2 = ln(2) Signup and view all the answers

How can the activity of a sample be used to find the decay constant?

By plotting activity versus time on a logarithmic scale, the gradient will be the negative of the decay constant. Signup and view all the answers

What are the three main isotopes of carbon in the atmosphere, and what is their approximate ratio?

C-12, C-13, and C-14, with a ratio of approximately 99% C-12, 1% C-13, and trace amounts of C-14. Signup and view all the answers

What is the purpose of using a mass spectrometer in radiocarbon dating?

To find the abundance of the active isotope in the sample. Signup and view all the answers

How can the half-life be estimated from a plot of activity versus time?

The time taken for the activity to half will give an estimation of the half-life. Signup and view all the answers

What is the relationship between the activity and the number of active isotopes?

𝐴𝐴 = 𝜆𝜆𝜆𝜆 Signup and view all the answers

What is the significance of the logarithmic scale in plotting activity versus time?

It allows us to obtain a straight line which represents ln(𝐴𝐴) = ln(𝐴𝐴0) − 𝜆𝜆𝜆𝜆. Signup and view all the answers

What is the underlying assumption of radiocarbon dating?

The ratio of C-12 to C-14 has remained constant throughout history Signup and view all the answers

Why is radiocarbon dating not suitable for samples much older than 5700 years?

The amount of C-14 becomes immeasurably small Signup and view all the answers

What is the process by which C-14 decays?

Beta emission Signup and view all the answers

What is the purpose of comparing the ratio of C-14 to C-12 in the dead tissue to the atmospheric composition?

To estimate the time since the organism's death Signup and view all the answers

What is the condition necessary for nuclear fusion to occur in stars?

High temperatures and pressures Signup and view all the answers

What is the source of the high temperatures and pressures in the core of stars?

Gravitational pressure generated by the outer layers of the star Signup and view all the answers

What is the alternative method used for dating samples older than 5700 years?

Rubidium dating Signup and view all the answers

Why is it necessary for living organisms to absorb C-14 during their lifetimes?

So that the ratio of C-14 to C-12 in the organism matches the atmospheric ratio Signup and view all the answers