Question 1

Given that the half-life for radium-226 is 1600 y, how long is the "quarter-life" (that is, the time for the radiation to decay to one-fourth of its initial level)?

Accepted Answer

The answer of Given that the half-life for radium-226 is...

Question 2

In the radioactive decay equation $^{210}_{84}$ Po* → $^{210}_{84}$Po + X, what is X?

Accepted Answer

The answer of In the radioactive decay equation $^{210}_{84}$ Po*...

Question 3

An α particle is also known as

Accepted Answer

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

Question 4

A stable nucleus contains many protons very close to each other, all positively charged. Why do the protons not fly apart due to mutual Coulomb repulsion?

Accepted Answer

A)  An attractive nuclear force in the nucleus counteracts the effect of the Coulomb forces. 
B)  There are an equal number of electrons in the nucleus which neutralize the protons. 
C)  The neutrons in the nucleus shield the protons from each other. 
D)  The Coulomb force does not operate within nuclei. 
E)  The gravity of the protons and neutrons overcomes their repulsion at such close distances. 
A)  An attractive nuclear force in the nucleus counteracts the effect of the Coulomb forces. 
B)  There are an equal number of electrons in the nucleus which neutralize the protons. 
C)  The neutrons in the nucleus shield the protons from each other. 
D)  The Coulomb force does not operate within nuclei. 
E)  The gravity of the protons and neutrons overcomes their repulsion at such close distances.

Question 5

Polonium-215, $^{215}_{84}$Po, undergoes alpha decay with a half-life of 1.8 ms.
(a) What percent of the original polonium-215 is left after 0.010 s?
(b) How many protons and neutrons does the daughter nucleus contain?

Accepted Answer

(a) 2.1%<sup> </sup> (

Question 6

The two strongest forces that act between protons in a nucleus are

Accepted Answer

A)  the weak nuclear and electromagnetic forces. 
B)  the weak nuclear and the gravitational forces. 
C)  the electrostatic and the gravitational forces. 
D)  the strong nuclear and the electrostatic forces. 
A)  the weak nuclear and electromagnetic forces. 
B)  the weak nuclear and the gravitational forces. 
C)  the electrostatic and the gravitational forces. 
D)  the strong nuclear and the electrostatic forces.

Question 7

How long will it take a 4.50-kBq sample of material to reach an activity level of 0.140 kBq if the half-life of the sample is 435 years?

Accepted Answer

A)  14,478 years 
B)  3245 years 
C)  2178 years 
D)  1993 years 
A)  14,478 years 
B)  3245 years 
C)  2178 years 
D)  1993 years

Question 8

Determine the missing product X in the following nuclear reaction: 
$
^{235}
_{92}
 U $+ neutron → $^{141}
_{56}
 Ba $+ X + 3 neutrons

Accepted Answer

The answer of Determine the missing product X in the...

Question 9

A sample containing 4.0 × 1018 atoms of a radioactive isotope decays with a half-life of 2.3 years. How many undecayed atoms are left after 3.7 years?

Accepted Answer

A)  2.5 × 1018 
B)  1.7 × 1018 
C)  1.3 × 1018 
D)  1.1 × 1018 
A)  2.5 × 1018 
B)  1.7 × 1018 
C)  1.3 × 1018 
D)  1.1 × 1018

Question 10

Determine the missing product X in the nuclear reaction 
$^{238}_{92}$ U + $^{1}_{0}$ n → X + 2β-.

Accepted Answer

Question 11

The half-life of tritium is 12.3 y. What is its mean life (time constant)?

Accepted Answer

The answer of The half-life of tritium is 12.3 y....

Question 12

The atomic mass unit is defined as

Accepted Answer

A)  the mass of a proton. 
B)  the mass of an electron. 
C)  the mass of a hydrogen-1 atom. 
D)  one twelfth the mass of a carbon-12 atom. 
E)  the mass of a carbon-12 nucleus. 
A)  the mass of a proton. 
B)  the mass of an electron. 
C)  the mass of a hydrogen-1 atom. 
D)  one twelfth the mass of a carbon-12 atom. 
E)  the mass of a carbon-12 nucleus.

Question 13

When an unstable nucleus decays by emitting an alpha particle, the atomic number Z of the nucleus

Accepted Answer

A)  increases by 4. 
B)  increases by 2. 
C)  decreases by 2. 
D)  decreases by 4. 
E)  remains unchanged. 
A)  increases by 4. 
B)  increases by 2. 
C)  decreases by 2. 
D)  decreases by 4. 
E)  remains unchanged.

Question 14

The chief hazard of radiation damage to living cells is

Accepted Answer

A)  due to heating. 
B)  due to ionization. 
C)  due to the creation of chemical impurities. 
D)  the creation of new isotopes within the body. 
E)  the creation of radioactive material within the body. 
A)  due to heating. 
B)  due to ionization. 
C)  due to the creation of chemical impurities. 
D)  the creation of new isotopes within the body. 
E)  the creation of radioactive material within the body.

Question 15

The activity of a sample reduces from 7.55 × $10 ^ { 9 }$ Bq to 5.11 × $10 ^ { 9 }$ 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 16

In the nuclear reaction $^{16}
_{8}
 O + 
^{1} 
_{0}
n → X + ^{4}
_{2}

He$, what is X?

Accepted Answer

A)  12C 
B)  13C 
C)  14C 
D)  15C 
E)  17O 
A)  12C 
B)  13C 
C)  14C 
D)  15C 
E)  17O

Question 17

An electron and a positron, both essentially at rest, annihilate each other, emitting two identical photons in the process. What is the wavelength of these photons? The mass of an electron or positron is 9.11 × 10-31 kg. 
(h = 6.626 × 10-34 J ∙ s, c = 3.00 × 108 m/s)

Accepted Answer

A)  1.21 × 10-12 pm 
B)  1.73 pm 
C)  2.42 pm 
D)  3.07 pm 
E)  3.46 pm 
A)  1.21 × 10-12 pm 
B)  1.73 pm 
C)  2.42 pm 
D)  3.07 pm 
E)  3.46 pm

Question 18

The unstable isotope 234Th decays by β emission with a half-life of 24.5 days. If the initial decay rate of the sample is 6.2 × $10^{17}$ Bq, what is the decay rate after 37 days?

Accepted Answer

Question 19

The neutral $^{27}_{13}$Al atom has a mass of 26.981539 u; a neutral hydrogen atom has a mass of 1.007825 u; a neutron has a mass of 1.008665 u; and a proton has a mass of 1.007277 u. What is the binding energy per nucleon for $^{27}_{13}$Al? (1 u = 931.5 MeV/c2)

Accepted Answer

A)  8.3 MeV 
B)  6.7 MeV 
C)  5.4 MeV 
D)  3.4 MeV 
E)  2.8 MeV 
A)  8.3 MeV 
B)  6.7 MeV 
C)  5.4 MeV 
D)  3.4 MeV 
E)  2.8 MeV

Question 20

In the nuclear reaction $^{ 16 } _{ 8 }O + ^{4}
_{2}
 He → X + ^{19}
_{10}
 Ne$ , what is X?

Accepted Answer

A)  proton 
B)  neutron 
C)  2H 
D)  3H 
E)  alpha particle 
A)  proton 
B)  neutron 
C)  2H 
D)  3H 
E)  alpha particle

Exam 30: Nuclear Physics

Given that the half-life for radium-226 is 1600 y, how long is the "quarter-life" (that is, the time for the radiation to decay to one-fourth of its initial level)?

In the radioactive decay equation 84210^{210}_{84}84210​ Po* → 84210^{210}_{84}84210​ Po + X, what is X?

An α particle is also known as

A stable nucleus contains many protons very close to each other, all positively charged. Why do the protons not fly apart due to mutual Coulomb repulsion?

Polonium-215, 84215^{215}_{84}84215​ Po, undergoes alpha decay with a half-life of 1.8 ms. (a) What percent of the original polonium-215 is left after 0.010 s? (b) How many protons and neutrons does the daughter nucleus contain?

The two strongest forces that act between protons in a nucleus are

How long will it take a 4.50-kBq sample of material to reach an activity level of 0.140 kBq if the half-life of the sample is 435 years?

Determine the missing product X in the following nuclear reaction: 92235U^{235}_{92} U 92235​U + neutron → 56141Ba^{141}_{56} Ba 56141​Ba + X + 3 neutrons

A sample containing 4.0 × 1018 atoms of a radioactive isotope decays with a half-life of 2.3 years. How many undecayed atoms are left after 3.7 years?

Determine the missing product X in the nuclear reaction 92238^{238}_{92}92238​ U + 01^{1}_{0}01​ n → X + 2β-.

The half-life of tritium is 12.3 y. What is its mean life (time constant)?

The atomic mass unit is defined as

When an unstable nucleus decays by emitting an alpha particle, the atomic number Z of the nucleus

The chief hazard of radiation damage to living cells is

The activity of a sample reduces from 7.55 × 10910 ^ { 9 }109 Bq to 5.11 × 10910 ^ { 9 }109 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?

In the nuclear reaction 816O+01n→X+24He^{16}_{8} O + ^{1} _{0}n → X + ^{4}_{2} He816​O+01​n→X+24​He , what is X?

An electron and a positron, both essentially at rest, annihilate each other, emitting two identical photons in the process. What is the wavelength of these photons? The mass of an electron or positron is 9.11 × 10-31 kg. (h = 6.626 × 10-34 J ∙ s, c = 3.00 × 108 m/s)

The unstable isotope 234Th decays by β emission with a half-life of 24.5 days. If the initial decay rate of the sample is 6.2 × 101710^{17}1017 Bq, what is the decay rate after 37 days?

The neutral 1327^{27}_{13}1327​ Al atom has a mass of 26.981539 u; a neutral hydrogen atom has a mass of 1.007825 u; a neutron has a mass of 1.008665 u; and a proton has a mass of 1.007277 u. What is the binding energy per nucleon for 1327^{27}_{13}1327​ Al? (1 u = 931.5 MeV/c2)

In the nuclear reaction 816O+24He→X+1019Ne^{ 16 } _{ 8 }O + ^{4}_{2} He → X + ^{19}_{10} Ne816​O+24​He→X+1019​Ne , what is X?

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In the radioactive decay equation $^{210}_{84}$ Po* → $^{210}_{84}$ Po + X, what is X?

Polonium-215, $^{215}_{84}$ Po, undergoes alpha decay with a half-life of 1.8 ms. (a) What percent of the original polonium-215 is left after 0.010 s? (b) How many protons and neutrons does the daughter nucleus contain?

Determine the missing product X in the following nuclear reaction: $^{235}_{92} U$ + neutron → $^{141}_{56} Ba$ + X + 3 neutrons

A sample containing 4.0 × 10¹⁸ atoms of a radioactive isotope decays with a half-life of 2.3 years. How many undecayed atoms are left after 3.7 years?

Determine the missing product X in the nuclear reaction $^{238}_{92}$ U + $^{1}_{0}$ n → X + 2β^-.

The activity of a sample reduces from 7.55 × $10 ^ { 9 }$ Bq to 5.11 × $10 ^ { 9 }$ 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?

In the nuclear reaction $^{16}_{8} O + ^{1} _{0}n → X + ^{4}_{2} He$ , what is X?

An electron and a positron, both essentially at rest, annihilate each other, emitting two identical photons in the process. What is the wavelength of these photons? The mass of an electron or positron is 9.11 × 10^-31 kg. (h = 6.626 × 10^-34 J ∙ s, c = 3.00 × 10⁸ m/s)

The unstable isotope ²³⁴Th decays by β emission with a half-life of 24.5 days. If the initial decay rate of the sample is 6.2 × $10^{17}$ Bq, what is the decay rate after 37 days?

The neutral $^{27}_{13}$ Al atom has a mass of 26.981539 u; a neutral hydrogen atom has a mass of 1.007825 u; a neutron has a mass of 1.008665 u; and a proton has a mass of 1.007277 u. What is the binding energy per nucleon for $^{27}_{13}$ Al? (1 u = 931.5 MeV/c²)

In the nuclear reaction $^{ 16 } _{ 8 }O + ^{4}_{2} He → X + ^{19}_{10} Ne$ , what is X?