$$R = 4.8 \times 10$$^{-15}$$ m

$$0.015 \times 931.49 = 13.97$$ MeV

Question 1

Which force is responsible for holding protons and neutrons together in the nucleus, despite the repulsive electromagnetic force between protons?

Accepted Answer

Strong nuclear force

Question 2

What is the radius of a nucleus with mass number $$A = 64$$ using the formula $$R = r_0$ A$$^{1/3}$$, where r_0$ = 1.2 	imes 10$$^{-15}$$ m?

Accepted Answer

$$R = 4.8 	imes 10$$^{-15}$$ m

Question 3

A sample of $$^{14}C $$has a half-life of 5730 years. If a bone contains 25% of its original $$^{14}C$$, how many half-lives have passed?

Accepted Answer

2

Question 4

Which of the following statements about isotopes is correct?

Accepted Answer

Isotopes have the same number of protons but different numbers of neutrons.

Question 5

What is the binding energy per nucleon for $$^{204}Pb if $$the total binding energy is 1607 MeV?

Accepted Answer

$$7.88$$ MeV

Question 6

Which nuclear decay process results in the emission of a positron?

Accepted Answer

Beta plus decay

Question 7

If a radioactive sample has an initial activity $$R_0$$ and a half-life $$t_{1/2}$$, what is its activity after $$t_{1/2}$$?

Accepted Answer

$$\frac{R_0$}{2}$$

Question 8

Which type of radiation is most likely to cause significant biological damage if internalized, such as in the lungs?

Accepted Answer

Alpha particles

Question 9

A $$^{238}U $$nucleus undergoes alpha decay. What is the resulting daughter nucleus?

Accepted Answer

$$^{234}Th$$

Question 10

What is the SI unit for absorbed dose of ionizing radiation?

Accepted Answer

Gray (Gy)

Question 11

Which equation describes the exponential decay of radioactive nuclei over time?

Accepted Answer

$$N(t) = N_0$ e$$^{-rt}$$

Question 12

If the mass defect for a nucleus is $$\Delta m = 0.015 u$$, what is the total binding energy in MeV?

Accepted Answer

$$0.015 	imes 931.49 = 13.97$$ MeV

Question 13

Which of the following is true about the line of stability for nuclei?

Accepted Answer

Stable nuclei for higher atomic numbers require more neutrons than protons.

Question 14

What is the main reason neutrons are needed in the nucleus for stability, especially in heavier elements?

Accepted Answer

Neutrons dilute the repulsive electromagnetic force between protons while maintaining strong force attraction.

Question 15

Which decay mechanism involves the emission of high-energy electromagnetic waves from an excited nucleus?

Accepted Answer

Gamma decay

Question 16

A radioactive sample has an initial number of nuclei $$N_0. $$After three half-lives, what fraction of the original nuclei remain?

Accepted Answer

$$\frac{1}{8}$$

Question 17

Which of the following is NOT a consequence of ionizing radiation exposure?

Accepted Answer

Inducing radioactivity in exposed objects

Question 18

What is the dose equivalent in Sieverts for an absorbed dose of 2 Gy with a relative biological effectiveness (RBE) of 1.5?

Accepted Answer

$$3 Sv$$

Question 19

Which isotope is commonly used for radioactive dating of ancient organic material?

Accepted Answer

$$^{14}C$$

Question 20

A $$^{11}C $$nucleus (Z = 6) decays to $$^{11}B (Z = 5). $$What type of nuclear decay has occurred?

Accepted Answer

Beta plus decay

Nuclear Physics: Structure, Stability, and Radioactivity

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