Deck 24: Nuclear Physics

Question 1

The smallest particle of any chemical element that can exist by itself and yet retain the qualities that distinguish it as that element is:

A) an electron
B) a proton
C) a neutron
D) an atom
E) a molecule

Answer 1

an atom

Question 2

The mass of an electron:

A) is almost the same as that of a neutron
B) is negative
C) equals that of a proton
D) is zero if the electron is at rest
E) is much less than that of a proton

Answer 2

is much less than that of a proton

Question 3

The mass of a neutron:

A) equals that of an electron
B) equals that of a proton
C) is a little more than that of a proton
D) is exactly that of a proton plus an electron
E) is as yet unmeasured

Answer 3

is a little more than that of a proton

Question 4

Let Z denote the atomic number and A denote the mass number of a nucleus. The number of neutrons in this nucleus is:

A) Z
B) A - Z
C) A - 2Z
D) A
E) 2A - Z

Question 5

The isotopes of an element:

A) cannot be separated at all
B) occur well separated in nature
C) have similar chemical behavior
D) cannot be separated by physical methods
E) have equal masses

Question 6

Bromine, with atomic mass 79.942 u, is composed of nearly equal amounts of two isotopes, one of which contains 79 nucleons per atom. The mass number of the other isotope is:

A) 78
B) 79
C) 80
D) 81
E) 82

Question 7

Volumes of atomic nuclei are proportional to:

A) the mass number
B) the atomic number
C) the total nuclear spin
D) the number of neutrons
E) none of these

Question 8

A proton in a large nucleus:

A) attracts all other protons
B) repels all other protons
C) repels all neutrons
D) attracts some protons and repels others
E) attracts some neutrons and repels others

Question 9

Two protons are about 10^-10 m apart. Their relative motion is chiefly determined by:

A) gravitational forces
B) electrical forces
C) nuclear forces
D) magnetic forces
E) torque due to electric dipole moments

Question 10

Stable nuclei generally:

A) have a greater number of protons than neutrons
B) have low mass numbers
C) have high mass numbers
D) are beta emitters
E) none of the above

Question 11

The greatest binding energy per nucleon occurs for nuclides with masses near that of:

A) helium
B) sodium
C) iron
D) mercury
E) uranium

Question 12

The half-life of radium is about 1600 years. If a rock initially contains 1 g of radium, the amount left after 8000 years will be about:

A) 200 mg
B) 63 mg
C) 31 mg
D) 16 mg
E) less than 1 mg

Question 13

Starting with a sample of pure ⁶⁶Cu, 7/8 of it decays into Zn in 15 minutes. The corresponding half-life is:

A) 15 minutes
B) 5 minutes
C) 7 minutes
D) 3.75 minutes
E) 10 minutes

Question 14

²¹⁰Bi (an isotope of bismuth) has a half-life of 5.0 days. The time for three-quarters of a sample of ²¹⁰Bi to decay is:

A) 2.5 days
B) 10 days
C) 15 days
D) 20 days
E) 3.75 days

Question 15

At the end of 14 min, 1/16 of a sample of radioactive polonium remains. The corresponding half-life is:

A) (7/8) min
B) (8/7) min
C) (7/4) min
D) (7/2) min
E) (14/3) min

Question 16

An alpha particle is:

A) a helium atom with two electrons removed
B) an aggregate of two or more electrons
C) a hydrogen atom
D) the ultimate unit of positive charge
E) sometimes negatively charged

Question 17

A nucleus with mass number A and atomic number Z emits an alpha particle. The mass number and atomic number, respectively, of the daughter nucleus are:

A) A, Z -2
B) A - 2, Z - 2
C) A - 2, Z
D) A - 4, Z
E) A - 4, Z - 2

Question 18

In an alpha decay the disintegration energy appears as:

A) photon energies
B) the kinetic energies of the alpha and the daughter nucleus
C) the excitation energy of the daughter nucleus
D) the excitation energy of the alpha particle
E) heat

Question 19

Rank the following collections of particles according to the total binding energy of all the particles in each collection, least to greatest.
Collection 1: ²⁴⁴Pu (Z = 94) nuceus alone
Collection 2: ²⁴⁰U (Z = 92) nucleus, $\alpha$ particle
Collection 3: ²⁴⁰U (Z = 92) nucleus, two separated protons, two separated neutrons

A) 1,2,3
B) 3,2,1
C) 2,1,3
D) 1,3,2
E) 2,3,1

Question 20

A beta particle is:

A) a helium nucleus
B) an electron or a positron
C) a radioactive element
D) any negative particle
E) a hydrogen atom

Question 21

Beta particles from various radioactive sources all have:

A) the same mass
B) the same speed
C) the same charge
D) the same deflection
E) the same energy in a magnetic field

Question 22

In addition to the daughter nucleus and an electron or positron, the products of a beta decay include:

A) a neutron
B) a neutrino
C) a proton
D) an alpha particle
E) no other particle

Question 23

⁶⁵Cu will be turned into ⁶⁶Cu, with no accompanying product except a gamma ray, if bombarded with:

A) protons
B) neutrons
C) deuterons
D) electrons
E) alpha particles

Question 24

Of the three common types of radiation (alpha, beta, gamma) from radioactive sources, electric charge is carried by:

A) only beta and gamma
B) only beta
C) only alpha and gamma
D) only alpha
E) only alpha and beta