Question 1

The half-life of ¹⁹N is 0.42 s.What is the decay constant for this isotope? A) 1.7 × 10^-11 Ci B) 1.7 s^-1 C) 1.1 s^-1 D) The decay constant is not defined for a half-life of less than one second.

Accepted Answer

The decay constant is given by the formula λ = ln2/T1/2 where T1/2 is the half-life of the isotope. Substituting the given value, we get λ = ln2/0.42 s ≈ 1.7 s^-1. Thus, the correct choice is B.

Question 2

Tritium (³H)has a half-life of 12.3 years and releases 0.0186 MeV energy per decay.What is the rate at which energy is released for a 3.0-gram sample of tritium? (N_A = 6.02 × 10²³ mol^-1,1 year = 3.16 × 10⁷ s,1 MeV = 1.6 × 10^-13 J,and m_t = 3.01605 u) A) 3.2 W B) 1.1 W C) 9.6 W D) 0.33 W

Accepted Answer

The rate of energy release is given by:$$Rate = \frac{Energy \ released \ per \ decay 	imes Number \ of \ decays \ per \ second}{Number \ of \ atoms \ in \ the \ sample}$$The number of decays per second is given by:$$Number \ of \ decays \ per \ second = \frac{ln2}{Half-life} 	imes Number \ of \ atoms \ in \ the \ sample$$The number of atoms in the sample is given by:$$Number \ of \ atoms \ in \ the \ sample = \frac{Mass \ of \ the \ sample}{Atomic \ mass \ of \ tritium}$$Substituting these expressions into the equation for the rate of energy release, we get:$$Rate = \frac{Energy \ released \ per \ decay 	imes ln2}{Half-life} 	imes \frac{Mass \ of \ the \ sample}{Atomic \ mass \ of \ tritium}$$Plugging in the given values, we get:$$Rate = \frac{0.0186 \ MeV 	imes ln2}{12.3 \ years} 	imes \frac{3.0 \ g}{3.01605 \ u} 	imes \frac{1 \ year}{3.16 	imes 10^7 \ s} 	imes \frac{1 \ MeV}{1.6 	imes 10^{-13} \ J}$$$$Rate = 3.2 \ W$$Therefore, the correct answer is A.

Question 3

Tritium (³H)has a half-life of 12.3 years and releases 0.0186 MeV energy per decay.What is the activity of a 9.0-gram sample of tritium? (N_A = 6.02 × 10²³ mol^-1,1 year = 3.16 × 10⁷ s,1 MeV = 1.6 × 10^-13 J,and m_t = 3.01605 u) A) 1.3 × 10¹⁶ Bq B) 1.1 × 10¹⁵ Bq C) 3.6 × 10¹⁴ Bq D) 3.2 × 10¹⁵ Bq

Accepted Answer

The activity (A) is calculated using A = λN, where λ = ln(2)/half-life. First, calculate the number of moles of tritium, then the number of atoms (N) using Avogadro's number. Convert the half-life to seconds and calculate λ. Finally, calculate the activity in Bq.

Question 4

What particle is emitted when ²³⁶Pa decays to ²³⁶U? (The atomic numbers of Pa and U are,respectively,91 and 92. ) A) beta (positron) B) alpha C) gamma quantum D) beta (electron)

Accepted Answer

Since the atomic number (Z) of the parent nucleus (Pa) is greater than that of the daughter nucleus (U), a beta decay must occur where an electron (beta particle) is emitted.

Question 5

About what fraction of the initial activity of a radioactive source remains after 10 half-lives? A) 1.0 × 10^-10 B) 9.8 × 10^-4 C) 5.0 × 10^-2 D) 3.9 × 10^-3

Accepted Answer

The answer of About what fraction of the initial activity...

Question 6

A deuteron is captured by an oxygen-16 atom which in turn emits a proton.What is the element and mass number of the product isotope?
A) oxygen-15
B) fluorine-15
C) nitrogen-15
D) oxygen-17

Accepted Answer

The answer of A deuteron is captured by an oxygen-16...

Question 7

The energy released from a nuclear reaction is equal to:
A) energy associated with momentum conservation.
B) the exothermic endothermy.
C) energy associated with the change in mass.
D) the total charge involved.

Accepted Answer

According to Einstein's famous equation E=mc^2, the energy released from a nuclear reaction is proportional to the change in mass. This is because a small amount (mass) of matter can be converted into a large amount of energy through a nuclear reaction. The energy is released due to the conversion of mass into energy, as described by Einstein's equation.

Question 8

What energy must be added or given off in a reaction where a helium atom is separated into two hydrogen atoms and two neutrons? (Atomic masses for each: hydrogen,1.007825 u;neutron,1.008665 u;helium,4.002602 u;also,1 u = 931.5 MeV/c². ) A) 28.3 MeV given off B) 20.7 MeV added C) 20.7 MeV given off D) 28.3 MeV added

Accepted Answer

To find the energy involved in separating a helium atom into two hydrogen atoms and two neutrons, we calculate the mass defect and then convert it to energy. The mass of the helium atom is 4.002602 u. The combined mass of the products (two hydrogen atoms and two neutrons) is (2 * 1.007825 u) + (2 * 1.008665 u) = 4.03322 u. The mass defect is the difference between the initial and final masses, which is 4.03322 u - 4.002602 u = 0.030618 u. Converting this mass defect into energy using E=mc^2 (where 1 u = 931.5 MeV/c^2), we get 0.030618 u * 931.5 MeV/u = 28.53 MeV. Since the final mass is greater than the initial mass, energy must be added to the system to make this transformation happen.

Question 9

What is the energy released for the reaction where the products are 0.0051 u less than the reactants? (1 u = 931.5 MeV/c²) A) 7.6 MeV B) 5.2 MeV C) 4.8 MeV D) 8.5 MeV

Accepted Answer

The answer of What is the energy released for the...

Question 10

Calculate the binding energy per nucleon of the Nucleus,given that the mass of this nucleus is 3.016029 u.(m_p = 1.007276 u,m_n = 1.008665,and 1 u = 931.5 MeV/c²) A) 2.66 MeV/nucleon B) 2.86 MeV/nucleon C) 2.45 MeV/nucleon D) 2.23 MeV/nucleon

Accepted Answer

The answer of Calculate the binding energy per nucleon of...

Question 11

What particle is emitted when ²⁰Na decays to ²⁰Ne? (The atomic numbers of Na and Ne are,respectively,11 and 10. ) A) beta (positron) B) gamma quantum C) alpha D) beta (electron)

Accepted Answer

When sodium-20 (Na-20) decays to neon-20 (Ne-20), it undergoes beta-plus decay, emitting a positron (beta particle) to decrease the atomic number from 11 to 10.

Question 12

What is the energy released (or gained signified by the minus sign)value of the reaction ? The mass of the alpha particle is 4.002602 u,of the nitrogen is 14.003074 u,of the oxygen is 15.994915 u,and of the hydrogen is 2.014102 u.(1 u = 931.5 MeV/c²) A) -3.11 MeV B) -3.34 MeV C) 3.11 MeV D) 3.34 MeV

Accepted Answer

The answer of What is the energy released (or gained...

Question 13

In the reaction 
,what are the mass number and the atomic number of the product designated by X?
A) 101,42
B) 102,44
C) 102,42
D) not given

Accepted Answer

The answer of In the reaction 
,what are the mass...

Question 14

The isotope ²³⁸U,which starts one of the natural radioactive series,decays first by alpha decay followed by two negative beta decays.At this point,what is the resulting isotope? A) ²³⁴Th (Z = 90 for Th. ) B) ²³⁶U C) ²³⁸U D) Some other uranium isotope not given above.

Accepted Answer

The answer of The isotope ²³⁸U,which starts one of the...

Question 15

One of the nuclear reactions that occurs is )What does the X represent in this equation?
A)
B)
C)
D)

Accepted Answer

The X in the nuclear reaction represents the isotope of the element being used. Only option B has a different isotope (2953) compared to the other options (2952, 2954, 2955).

Question 16

An alpha particle (mass = 6.68 × 10−²⁷ kg)is emitted from a radioactive nucleus with an energy of 6.22 MeV.How fast is the alpha particle moving in m/s? (1 MeV = 1.6 × 10−¹³ J) A) 3.70 × 10⁶ m/s B) 1.73 × 10⁷ m/s C) 1.55 × 10⁷ m/s D) 1.85 × 10⁶ m/s

Accepted Answer

Kinetic energy = 1/2 mv^26.22 MeV = (1/2) (6.68 × 10−27 kg) v^2v = 1.73 × 10^7 m/s

Question 17

Which of the following methods of decay does not result in an element different from that of the original parent nucleus?
A) alpha followed by negative beta followed by another negative beta
B) alpha followed by beta
C) alpha followed by gamma followed by another gamma
D) alpha followed by positive beta followed by another positive beta

Accepted Answer

The answer of Which of the following methods of decay...

Quiz 30: Nuclear Energy and Elementary Particles: Part A

The half-life of ¹⁹N is 0.42 s.What is the decay constant for this isotope?

Tritium (³H) has a half-life of 12.3 years and releases 0.0186 MeV energy per decay.What is the rate at which energy is released for a 3.0-gram sample of tritium? (N_A = 6.02 × 10²³ mol^-1,1 year = 3.16 × 10⁷ s,1 MeV = 1.6 × 10^-13 J,and m_t = 3.01605 u)

Tritium (³H) has a half-life of 12.3 years and releases 0.0186 MeV energy per decay.What is the activity of a 9.0-gram sample of tritium? (N_A = 6.02 × 10²³ mol^-1,1 year = 3.16 × 10⁷ s,1 MeV = 1.6 × 10^-13 J,and m_t = 3.01605 u)

What particle is emitted when ²³⁶Pa decays to ²³⁶U? (The atomic numbers of Pa and U are,respectively,91 and 92. )

About what fraction of the initial activity of a radioactive source remains after 10 half-lives?

A deuteron is captured by an oxygen-16 atom which in turn emits a proton.What is the element and mass number of the product isotope?

The energy released from a nuclear reaction is equal to:

What energy must be added or given off in a reaction where a helium atom is separated into two hydrogen atoms and two neutrons? (Atomic masses for each: hydrogen,1.007825 u;neutron,1.008665 u;helium,4.002602 u;also,1 u = 931.5 MeV/c². )

What is the energy released for the reaction where the products are 0.0051 u less than the reactants? (1 u = 931.5 MeV/c²)

Calculate the binding energy per nucleon of the Nucleus,given that the mass of this nucleus is 3.016029 u.(m_p = 1.007276 u,m_n = 1.008665,and 1 u = 931.5 MeV/c²)

What particle is emitted when ²⁰Na decays to ²⁰Ne? (The atomic numbers of Na and Ne are,respectively,11 and 10. )

What is the energy released (or gained signified by the minus sign) value of the reaction ? The mass of the alpha particle is 4.002602 u,of the nitrogen is 14.003074 u,of the oxygen is 15.994915 u,and of the hydrogen is 2.014102 u.(1 u = 931.5 MeV/c²)

In the reaction ,what are the mass number and the atomic number of the product designated by X?

The isotope ²³⁸U,which starts one of the natural radioactive series,decays first by alpha decay followed by two negative beta decays.At this point,what is the resulting isotope?

One of the nuclear reactions that occurs is ) What does the X represent in this equation?

An alpha particle (mass = 6.68 × 10−²⁷ kg) is emitted from a radioactive nucleus with an energy of 6.22 MeV.How fast is the alpha particle moving in m/s? (1 MeV = 1.6 × 10−¹³ J)

Which of the following methods of decay does not result in an element different from that of the original parent nucleus?

Quiz 30: Nuclear Energy and Elementary Particles: Part A

The half-life of 19N is 0.42 s.What is the decay constant for this isotope?

Tritium (3H) has a half-life of 12.3 years and releases 0.0186 MeV energy per decay.What is the rate at which energy is released for a 3.0-gram sample of tritium? (NA = 6.02 × 1023 mol-1,1 year = 3.16 × 107 s,1 MeV = 1.6 × 10-13 J,and mt = 3.01605 u)

Tritium (3H) has a half-life of 12.3 years and releases 0.0186 MeV energy per decay.What is the activity of a 9.0-gram sample of tritium? (NA = 6.02 × 1023 mol-1,1 year = 3.16 × 107 s,1 MeV = 1.6 × 10-13 J,and mt = 3.01605 u)

What particle is emitted when 236Pa decays to 236U? (The atomic numbers of Pa and U are,respectively,91 and 92. )