Q: Given the following data for a nucleus: mass of nucleus = 55.9349 amu, mass of 26 protons = 26 × 1.00728 amu, mass of 30 neutrons = 30 × 1.00866 amu. What is the mass defect?

$$(26 \times 1.00728 + 30 \times 1.00866) - 55.9349 = 0.5284$$ amu

Q: The binding energy per nucleon for a nucleus can be calculated using which of the following equations?

$$\text{Binding energy per nucleon} = \frac{\Delta m \times c^2$}{A}$$

Q: A nuclide has a mass defect of 0.1 amu. What is the binding energy in MeV? (1 amu = $$1.492 \times 10$$^{-10}$$ J, 1$ MeV = 1.602$$ \times $$10^{-13} J)$$

$$\frac{0.1 \times 1.492 \times 10$$^{-10}$$}{1.602 \times 10$$^{-13}$$} = 93.2$$ MeV

Question 1

Which of the following best describes the term 'mass defect' in nuclear chemistry?

Accepted Answer

The difference between the mass of a nucleus and the sum of the masses of its individual protons and neutrons.

Question 2

A nuclide of $$^{14}_{6}C$$ undergoes beta decay. Which of the following correctly represents the balanced nuclear equation for this process?

Accepted Answer

$$^{14}_{6}C \$$rightarrow ^{14}$$_{7}N $$+ ^{0}$$_{-1}e$$

Question 3

Which of the following statements about the strong force is correct?

Accepted Answer

It is the force that holds protons and neutrons together in the nucleus.

Question 4

A radioactive isotope has a half-life of 10 years. If you start with 80 grams, how much will remain after 30 years?

Accepted Answer

10 grams

Question 5

Which of the following nuclear processes is responsible for the energy produced in the Sun?

Accepted Answer

Nuclear fusion

Question 6

Given the following data for a nucleus: mass of nucleus = 55.9349 amu, mass of 26 protons = 26 × 1.00728 amu, mass of 30 neutrons = 30 × 1.00866 amu. What is the mass defect?

Accepted Answer

$$(26 	imes 1.00728 + 30 	imes 1.00866) - 55.9349 = 0.5284$$ amu

Question 7

Which of the following nuclides is most likely to undergo electron capture rather than beta decay?

Accepted Answer

A nuclide with a low N/Z ratio

Question 8

The binding energy per nucleon for a nucleus can be calculated using which of the following equations?

Accepted Answer

$$	ext{Binding energy per nucleon} = \frac{\Delta m 	imes c^2$}{A}$$

Question 9

Which of the following is a correct statement about radioactive decay kinetics?

Accepted Answer

Radioactive decay follows first-order kinetics, where $$\ln(N_t/N_0$) = -kt.$$

Question 10

A sample of $$^{60}Co$$ has an initial activity of 1000 counts per minute. After 10.5 years, the activity drops to 250 counts per minute. What is the half-life of $$^{60}Co$$?

Accepted Answer

5.25 years

Question 11

Which of the following best describes nuclear fission?

Accepted Answer

The splitting of a heavy nucleus into two lighter nuclei, releasing energy.

Question 12

Which of the following is a real-world application of U-235 fission?

Accepted Answer

Nuclear power plants generating electricity

Question 13

A nuclide has a mass defect of 0.1 amu. What is the binding energy in MeV? (1 amu = $$1.492 	imes 10$$^{-10}$$ J, 1$ MeV = 1.602$$ 	imes $$10^{-13} J)$$

Accepted Answer

$$\frac{0.1 	imes 1.492 	imes 10$$^{-10}$$}{1.602 	imes 10$$^{-13}$$} = 93.2$$ MeV

Question 14

Which of the following nuclear reactions is an example of fusion?

Accepted Answer

$$^{2}_{1}H $$+ ^{3}$$_{1}H \$$rightarrow ^{4}$$_{2}He $$+ ^{1}$$_{0}n$$

Question 15

Which of the following statements about the N/Z ratio is correct?

Accepted Answer

Nuclides with a high N/Z ratio tend to undergo beta decay to decrease the number of neutrons.

Question 16

A radioactive sample decays from 200 mg to 25 mg in 24 hours. What is the half-life of the isotope?

Accepted Answer

6 hours

Question 17

Which of the following is NOT a fundamental particle found in the nucleus?

Accepted Answer

Electron

Question 18

Which equation correctly relates the decay constant $$k to $$the half-life $$t_{1/2}$$?

Accepted Answer

$$t_{1/2} = \frac{0.693}{k}$$

Question 19

Which of the following best describes the process of electron capture?

Accepted Answer

A nucleus absorbs an inner orbital electron, converting a proton into a neutron.

Question 20

Which of the following is a balanced nuclear equation for the fission of $$^{235}_{92}U by a $$neutron?

Accepted Answer

$$^{235}_{92}U $$+ ^{1}$$_{0}n \$$rightarrow ^{141}$$_{56}Ba $$+ ^{92}$$_{36}Kr + 3$$ ^{1}$$_{0}n$$

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