Question 1

Except for such nuclear processes as nuclear reactors, nuclear bombs, and radioactivity, all of the common forces we see around us daily are due to just two underlying or "fundamental" forces. One of these two forces is the electromagnetic force. The other is

Accepted Answer

The gravitational force is one of the two fundamental forces that govern the interactions we observe daily, alongside the electromagnetic force.

Question 2

How does the mass of a ⁴He nucleus compare with the mass of a ³H nucleus? 2 1 A) ⁴He is 4/3 times as massive, i.e., 33% more massive. B) They have about the same mass. C) ⁴He is four times as massive. D) ⁴He is twice as massive. E) ⁴He is 3/2 times as massive, i.e., 50% more massive.

Accepted Answer

The answer of How does the mass of a <sup>4...

Question 3

Mutations are

Accepted Answer

Mutations are crucial for evolution as they introduce genetic variation. They can be caused by various factors, including radioactivity.

Question 4

The isotope ²³⁸U alpha decays to the daughter nucleus

Accepted Answer

When ²³⁸U undergoes alpha decay, it emits an alpha particle (which is a helium nucleus, ⁴He), resulting in a daughter nucleus of ²³⁴Th.

Question 5

At Chernobyl, one of the harmful radioactive isotopes was ¹³¹I, a beta emitter with a halflife of 8 days. The mass number of the nucleus that remains after this isotope decays is

Accepted Answer

Beta emission decreases the atomic number by 1, so the mass number of the nucleus that remains after this isotope decays is 129.

Question 6

Two different isotopes of the same element have

Accepted Answer

Isotopes of the same element have the same number of protons but different numbers of neutrons, which gives them different atomic masses.

Question 7

How many protons and how many neutrons are in the ⁵⁶Fe nucleus?

Accepted Answer

The atomic number of iron (Fe) is 26, which means it has 26 protons. The mass number is 56, so the number of neutrons is 56 - 26 = 30.

Question 8

If you start with one gram of pure ¹⁴C [half- life 6000 years], the amount remaining after 36,000 years will be

Accepted Answer

The answer of If you start with one gram of...

Question 9

The discoverer of radium was

Accepted Answer

Marie Curie discovered radium, along with her husband Pierre Curie, in 1898.

Question 10

Compared to natural background radiation, the amount of radiation received by U.S. citizens from normally operating nuclear power plants is

Accepted Answer

The radiation received from normally operating nuclear power plants is very much less than natural background radiation. Natural sources like cosmic rays and radon contribute far more to the average person's radiation exposure.

Question 11

When the radioactive isotope ¹⁴C undergoes beta- decay, the atomic number of the resulting nucleus is

Accepted Answer

Beta decay involves the conversion of a neutron into a proton and an electron. The atomic number of the resulting nucleus is increased by 1. Therefore, the atomic number of the resulting nucleus is 7.

Question 12

Consider the three following forces: gravitational, electromagnetic, and strong nuclear. Of these three, which one or ones have significant effects [i.e., experimentally detectable effects] within the nucleus?

Accepted Answer

Within the nucleus, the electromagnetic force and the strong nuclear force have significant effects. The electromagnetic force acts between charged particles, such as protons, while the strong nuclear force binds protons and neutrons together. The gravitational force is negligible at the nuclear scale due to its relative weakness compared to the other forces.

Question 13

The half- life of a radioactive isotope is

Accepted Answer

The half-life of a radioactive isotope is the time required for half of the nuclei in a large sample to decay.

Question 14

One way in which the ionizing radiation occurring naturally in the environment has been beneficial to the human race is

Accepted Answer

Ionizing radiation can cause mutations, which are a driving force of evolution, leading to genetic diversity and adaptation.

Question 15

If a radioactive isotope has a one year halflife, what fraction will remain after 5 years?

Accepted Answer

After 5 years, the isotope will have gone through 5 half-lives. Each half-life reduces the remaining amount by half, so (1/2)^5 = 1/32 of the original amount will remain.

Question 16

The half- life of radium is

Accepted Answer

The half-life of a radioactive substance is defined as the time required for half of a large number of its atoms to decay.

Question 17

Regarding the question of the precise time at which a radioactive nucleus will decay:

Accepted Answer

Radioactive decay is governed by quantum mechanics, which introduces inherent uncertainties, making the exact time of decay statistically predictable rather than precisely predictable.

Question 18

A saber- toothed- tiger's bones contain 1/32 of the amount of ¹⁴C that is contained in the bone material of living animals. The half- life of ¹⁴C is 6000 years. From this information, we can conclude

Accepted Answer

The half-life formula can be used to calculate the time since death: (1/2)^(t/6000) = 1/32. Solving for t gives approximately 30,000 years.

Question 19

Where does most of Earth's ¹⁴C come from?

Accepted Answer

Most of Earth's carbon-14 is formed in the atmosphere through the interaction of cosmic rays with nitrogen atoms, converting them into carbon-14.

Question 20

How do ³H and ³He differ? 1 2

Accepted Answer

The answer of How do ³H and ³He...

Quiz 14: The Nucleus and Radioactivity: an New Force

Except for such nuclear processes as nuclear reactors, nuclear bombs, and radioactivity, all of the common forces we see around us daily are due to just two underlying or "fundamental" forces. One of these two forces is the electromagnetic force. The other is

How does the mass of a 4 He nucleus compare with the mass of a 3 H nucleus? 2 1 A) 4 He is 4/3 times as massive, i.e., 33% more massive. B) They have about the same mass. C) 4 He is four times as massive. D) 4 He is twice as massive. E) 4 He is 3/2 times as massive, i.e., 50% more massive.