Question 1

In beta-minus decay

Accepted Answer

A)  an electron is emitted. 
B)  a proton is emitted. 
C)  a proton is transformed into a neutron. 
D)  a neutron is emitted. 
E)  an electron decays into another particle. 
A)  an electron is emitted. 
B)  a proton is emitted. 
C)  a proton is transformed into a neutron. 
D)  a neutron is emitted. 
E)  an electron decays into another particle. A

Question 2

The atomic number and mass number for calcium-39 are 20 and 39, respectively. How many neutrons are in one atom?

Accepted Answer

A)  39 
B)  19 
C)  59 
D)  20 
E)  1 
A)  39 
B)  19 
C)  59 
D)  20 
E)  1 B

Question 3

Atomic nuclei that are all isotopes of an element all have the same

Accepted Answer

A)  number of nucleons. 
B)  number of protons. 
C)  mass. 
D)  number of neutrons. 
A)  number of nucleons. 
B)  number of protons. 
C)  mass. 
D)  number of neutrons. B

Question 4

The atomic number of an atom is equal to the number of what particles in the nucleus?

Accepted Answer

A)  electrons 
B)  nucleons 
C)  positrons. 
D)  protons 
E)  neutrons 
A)  electrons 
B)  nucleons 
C)  positrons. 
D)  protons 
E)  neutrons

Question 5

The activity of a sample reduces from $7.55 \times 10 ^ { 9 } \mathrm {~Bq}$ to $5.11 \times 10 ^ { 9 } \mathrm {~Bq}$ in $5.50$ months.
(a) What is its half life?
(b) How many months from the start must one wait for the activity to decrease to $10 \%$ of its original value?

Accepted Answer

(a) 9.77 m

Question 6

Scandium ${ } _ { 21 } ^ { 43 }$ Sc decays by emitting a positron. What isotope is the product of this decay?

Accepted Answer

A)  ${ } _ { 21 } ^ { 43 } \mathrm { Ca }$ 
B)  ${ } _ { 21 } ^ { 45 } \mathrm { Sc }$ 
C)  ${ } _ { 21 } ^ { 43 } \mathrm { Sc }$ 
D)  ${ } _ { 20 } ^ { 44 } \mathrm { Ca }$ 
E)  ${ } _ { 22 } ^ { 44 } \mathrm { Ti }$ 
A)  ${ } _ { 21 } ^ { 43 } \mathrm { Ca }$ 
B)  ${ } _ { 21 } ^ { 45 } \mathrm { Sc }$ 
C)  ${ } _ { 21 } ^ { 43 } \mathrm { Sc }$ 
D)  ${ } _ { 20 } ^ { 44 } \mathrm { Ca }$ 
E)  ${ } _ { 22 } ^ { 44 } \mathrm { Ti }$

Question 7

The symbol for a certain isotope of radium is ${ } _ { 88 } ^ { 226 }$ Ra. How many nucleons are there in the nucleus of this isotope?

Accepted Answer

A)  314 
B)  226 
C)  214 
D)  138 
E)  88 
A)  314 
B)  226 
C)  214 
D)  138 
E)  88

Question 8

Starting with ${ } _ { 92 } ^ { 235 } \mathrm { U }$, assume that the following three decays occur in sequence:
(1) alpha decay
(2) beta-minus decay
(3) alpha decay
Determine the correct isotope that is left after each decay.

Accepted Answer

The answer of Starting with \({ } _ { 92...

Question 9

Calculate the estimated density of the nucleus of ${ } _ { 38 } ^ { 90 } \mathrm { Sr } ? \left( m _ { \text {neutron } } \approx m _ { \text {proton } } = 1.67 \times 10 ^ { - 27 } \mathrm {~kg} \right.$ )

Accepted Answer

A)  greater than $3.0 \times 10 ^ { 20 } \mathrm {~kg} / \mathrm { m } ^ { 3 }$ 
B)  $2.3 \times 10 ^ { 17 } \mathrm {~kg} / \mathrm { m } ^ { 3 }$ 
C)  $2.0 \times 10 ^ { 15 } \mathrm {~kg} / \mathrm { m } ^ { 3 }$ 
D)  $2.1 \times 10 ^ { 19 } \mathrm {~kg} / \mathrm { m } ^ { 3 }$ 
E)  $90 \mathrm {~kg} / \mathrm { m } ^ { 3 }$ 
A)  greater than $3.0 \times 10 ^ { 20 } \mathrm {~kg} / \mathrm { m } ^ { 3 }$ 
B)  $2.3 \times 10 ^ { 17 } \mathrm {~kg} / \mathrm { m } ^ { 3 }$ 
C)  $2.0 \times 10 ^ { 15 } \mathrm {~kg} / \mathrm { m } ^ { 3 }$ 
D)  $2.1 \times 10 ^ { 19 } \mathrm {~kg} / \mathrm { m } ^ { 3 }$ 
E)  $90 \mathrm {~kg} / \mathrm { m } ^ { 3 }$

Question 10

The radius $R$ of a nucleus of mass number $A$ is given by $R = R _ { 0 } A ^ { 1 / 3 }$, where $R _ { 0 } = 1.2 \times$ $10 ^ { - 15 } \mathrm {~m}$, calculate the density of a nucleus that has contains 57 protons and 82 neutrons. The mass of a nucleon (proton or neutron) is $1.67 \times 10 ^ { - 27 } \mathrm {~kg}$.

Accepted Answer

The answer of The radius $R$ of a nucleus of...

Question 11

An air sample is contaminated with $15 \mathrm { O }$, which has a half-life of $2.03$ minutes. You can pass it through a long pipe to allow it to decay until it can be safely released into the atmosphere. If the speed of the gas in the pipe is $1.1 \mathrm {~m} / \mathrm { s }$, how long must the pipeline be for the sample to decay to $3.0 \%$ of its original activity?

Accepted Answer

A)  $8.0 \mathrm {~m}$ 
B)  $250 \mathrm {~m}$ 
C)  $680 \mathrm {~m}$ 
D)  $72 \mathrm {~m}$ 
A)  $8.0 \mathrm {~m}$ 
B)  $250 \mathrm {~m}$ 
C)  $680 \mathrm {~m}$ 
D)  $72 \mathrm {~m}$

Question 12

A radioactive isotope of atomic number $Z$ emits a beta-minus particle, and then the daughter nucleus emits a gamma ray. What is the atomic number of the resulting nucleus after both processes?

Accepted Answer

A)  $Z - 2$ 
B)  $Z + 1$ 
C)  $Z - 1$ 
D)  $Z - 3$ 
A)  $Z - 2$ 
B)  $Z + 1$ 
C)  $Z - 1$ 
D)  $Z - 3$

Question 13

The atom $40 \mathrm {~K}$ decays radioactively to the gas $40 \mathrm { Ar }$. An ancient rock is found to contain enough $40 \mathrm { Ar }$ gas to indicate that $77.0 \%$ of the $40 \mathrm {~K}$ in the rock has decayed to $40 \mathrm { Ar }$ ince the rock solidified. (Any previous argon would have boiled out of liquid rock.) How long ago did the rock solidify? The half-life of $40 \mathrm {~K}$ is $1.25$ billion years.

Accepted Answer

A)  $0.471$ billion years 
B)  $2.65$ billion years 
C)  $0.324$ billion years 
D)  $1.80$ billion years 
A)  $0.471$ billion years 
B)  $2.65$ billion years 
C)  $0.324$ billion years 
D)  $1.80$ billion years

Question 14

An $\alpha$ particle is also known as

Accepted Answer

A)  a high-energy photon. 
B)  a positron. 
C)  a helium nucleus. 
D)  an electron. 
A)  a high-energy photon. 
B)  a positron. 
C)  a helium nucleus. 
D)  an electron.

Question 15

Uranium-238 decays into thorium-234 plus an alpha particle. The known masses are
$$\begin{array} { l l } 
{ } _ { 2 } ^ { 4 } \mathrm { He } : & 4.002603 \mathrm { u } \
{ } _ { 90 } ^ { 224 } \mathrm { Th } : & 234.043583 \mathrm { u } \
{ } _ { 92 } ^ { 238 } \mathrm { U } : & 238.050786 \mathrm { u }
\end{array}$$
How much energy is released in this process? $\left( 1 \mathrm { u } = 931.5 \mathrm { MeV } / c ^ { 2 } \right)$

Accepted Answer

A)  $3.18 \mathrm { MeV }$ 
B)  $4.28 \mathrm { MeV }$ 
C)  $5.05 \mathrm { MeV }$ 
D)  $3.76 \mathrm { MeV }$ 
E)  $2.89 \mathrm { MeV }$ 
A)  $3.18 \mathrm { MeV }$ 
B)  $4.28 \mathrm { MeV }$ 
C)  $5.05 \mathrm { MeV }$ 
D)  $3.76 \mathrm { MeV }$ 
E)  $2.89 \mathrm { MeV }$

Question 16

What should be the approximate diameter (in fm) of a nucleus containing 92 protons and
143 neutrons?

Accepted Answer

The answer of What should be the approximate diameter (in...

Question 17

Today, uranium contains $0.72 \%$ 235U (half-life $= 0.70$ billion years) and $99.28 \% 238 \cup$ (half-life $=$ $4.5$ billion years). At a time $1.9$ billion years ago, what was the fraction of $235 \mathrm { U }$ in uranium?

Accepted Answer

A)  $3.53 \%$ 
B)  $4.90 \%$ 
C)  $6.76 \%$ 
D)  $4.72 \%$ 
A)  $3.53 \%$ 
B)  $4.90 \%$ 
C)  $6.76 \%$ 
D)  $4.72 \%$

Question 18

What is true of an element of atomic number 15 that has an isotope of mass number 32? (There could be more than one correct choice.)

Accepted Answer

A)  the number of neutrons in the nucleus is 17. 
B)  the number of protons in the nucleus is 15. 
C)  the number of neutrons in the nucleus is 15. 
D)  the number of protons in the nucleus is 32. 
E)  the number of nucleons in the nucleus is 47. 
A)  the number of neutrons in the nucleus is 17. 
B)  the number of protons in the nucleus is 15. 
C)  the number of neutrons in the nucleus is 15. 
D)  the number of protons in the nucleus is 32. 
E)  the number of nucleons in the nucleus is 47.

Question 19

The symbol for a certain isotope of polonium is ${ } _ { 84 } ^ { 214 }$ Po. How many neutrons are there in the nucleus of this isotope?

Accepted Answer

A)  314 
B)  214 
C)  84 
D)  298 
E)  130 
A)  314 
B)  214 
C)  84 
D)  298 
E)  130

Question 20

The decay constant of radon-222 is $0.181 \mathrm {~d} - 1$. If a sample of radon initially contains $6.00 \times 10 ^ { 8 }$ radon atoms, how many of them are left after $10.0 \mathrm {~d}$ ?

Accepted Answer

A)  $8.56 \times 10 ^ { 8 }$ 
B)  $9.82 \times 10 ^ { 7 }$ 
C)  $8.34 \times 10 ^ { 8 }$ 
D)  $7.67 \times 10 ^ { 7 }$
Е) $7.29 \times 10 ^ { 8 }$ 
A)  $8.56 \times 10 ^ { 8 }$ 
B)  $9.82 \times 10 ^ { 7 }$ 
C)  $8.34 \times 10 ^ { 8 }$ 
D)  $7.67 \times 10 ^ { 7 }$
Е) $7.29 \times 10 ^ { 8 }$

Exam 30: Nuclear Physics and Radioactivity

In beta-minus decay

The atomic number and mass number for calcium-39 are 20 and 39, respectively. How many neutrons are in one atom?

Atomic nuclei that are all isotopes of an element all have the same

The atomic number of an atom is equal to the number of what particles in the nucleus?

Scandium 2143{ } _ { 21 } ^ { 43 }2143​ Sc decays by emitting a positron. What isotope is the product of this decay?

The symbol for a certain isotope of radium is 88226{ } _ { 88 } ^ { 226 }88226​ Ra. How many nucleons are there in the nucleus of this isotope?

Starting with 92235U{ } _ { 92 } ^ { 235 } \mathrm { U }92235​U , assume that the following three decays occur in sequence: (1) alpha decay (2) beta-minus decay (3) alpha decay Determine the correct isotope that is left after each decay.

A radioactive isotope of atomic number ZZZ emits a beta-minus particle, and then the daughter nucleus emits a gamma ray. What is the atomic number of the resulting nucleus after both processes?

An α\alphaα particle is also known as

Uranium-238 decays into thorium-234 plus an alpha particle. The known masses are : 4.002603 : 234.043583 : 238.050786 How much energy is released in this process? (1u=931.5MeV/c2)\left( 1 \mathrm { u } = 931.5 \mathrm { MeV } / c ^ { 2 } \right)(1u=931.5MeV/c2)

What should be the approximate diameter (in fm) of a nucleus containing 92 protons and 143 neutrons?

Today, uranium contains 0.72%0.72 \%0.72% 235U (half-life =0.70= 0.70=0.70 billion years) and 99.28%238∪99.28 \% 238 \cup99.28%238∪ (half-life === 4.54.54.5 billion years). At a time 1.91.91.9 billion years ago, what was the fraction of 235U235 \mathrm { U }235U in uranium?

What is true of an element of atomic number 15 that has an isotope of mass number 32? (There could be more than one correct choice.)

The symbol for a certain isotope of polonium is 84214{ } _ { 84 } ^ { 214 }84214​ Po. How many neutrons are there in the nucleus of this isotope?

The decay constant of radon-222 is 0.181 d−10.181 \mathrm {~d} - 10.181 d−1 . If a sample of radon initially contains 6.00×1086.00 \times 10 ^ { 8 }6.00×108 radon atoms, how many of them are left after 10.0 d10.0 \mathrm {~d}10.0 d ?

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Filters

Scandium ${ } _ { 21 } ^ { 43 }$ Sc decays by emitting a positron. What isotope is the product of this decay?

The symbol for a certain isotope of radium is ${ } _ { 88 } ^ { 226 }$ Ra. How many nucleons are there in the nucleus of this isotope?

Starting with ${ } _ { 92 } ^ { 235 } \mathrm { U }$ , assume that the following three decays occur in sequence: (1) alpha decay (2) beta-minus decay (3) alpha decay Determine the correct isotope that is left after each decay.

A radioactive isotope of atomic number $Z$ emits a beta-minus particle, and then the daughter nucleus emits a gamma ray. What is the atomic number of the resulting nucleus after both processes?

An $\alpha$ particle is also known as

Uranium-238 decays into thorium-234 plus an alpha particle. The known masses are : 4.002603 : 234.043583 : 238.050786 How much energy is released in this process? $\left( 1 \mathrm { u } = 931.5 \mathrm { MeV } / c ^ { 2 } \right)$

Today, uranium contains $0.72 \%$ 235U (half-life $= 0.70$ billion years) and $99.28 \% 238 \cup$ (half-life $=$ $4.5$ billion years). At a time $1.9$ billion years ago, what was the fraction of $235 \mathrm { U }$ in uranium?

The symbol for a certain isotope of polonium is ${ } _ { 84 } ^ { 214 }$ Po. How many neutrons are there in the nucleus of this isotope?

The decay constant of radon-222 is $0.181 \mathrm {~d} - 1$ . If a sample of radon initially contains $6.00 \times 10 ^ { 8 }$ radon atoms, how many of them are left after $10.0 \mathrm {~d}$ ?