# The energy equivalent of $$1$$ g of substance is: 1. $$8.3\times10^{13}~\text{J}$$ 2. $$9\times10^{13}~\text{J}$$ 3. $$7.7\times10^{13}~\text{J}$$ 4. $$11\times10^{13}~\text{J}$$

Subtopic: Â Nuclear Binding Energy |
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We are given the following atomic masses:

${}_{92}{}^{238}\mathrm{U}$ = 238.05079 u, ${}_{2}{}^{4}\mathrm{He}$= 4.00260 u

${}_{90}{}^{234}\mathrm{Th}$ = 234.04363 u, ${}_{1}{}^{1}\mathrm{H}$= 1.00783 u

${}_{91}{}^{237}\mathrm{Pa}$= 237.05121 u

Here the symbol Pa is for the element protactinium (Z = 91).

The energy released during the alpha decay of ${}_{92}{}^{238}\mathrm{U}$ is:

1. 6.14 MeV

2. 7.68 MeV

3. 4.25 MeV

4. 5.01 MeV

Subtopic: Â Nuclear Binding Energy |
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We are given the following atomic masses:

${}_{92}{}^{238}\mathrm{U}$ = 238.05079 u, ${}_{2}{}^{4}\mathrm{He}$= 4.00260 u

${}_{90}{}^{234}\mathrm{Th}$ = 234.04363 u, ${}_{1}{}^{1}\mathrm{H}$= 1.00783 u

${}_{91}{}^{237}\mathrm{Pa}$= 237.05121 u

Here the symbol Pa is for the element protactinium (Z = 91).

Then:

1. ${}_{92}{}^{238}\mathrm{U}$ can not spontaneously emit a proton.

2. ${}_{92}{}^{238}\mathrm{U}$ can spontaneously emit a proton.

3. The Q-value of the process is negative.

4. Both (1) and (3)

Subtopic: Â Nuclear Binding Energy |
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The energy required in $$\text{MeV/c}^2$$ to separate $${ }_8^{16} \mathrm{O}$$ into its constituents is:
(Given: mass defect for $${ }_8^{16} \mathrm{O}=0.13691~ \text{amu}$$)
1. $$127.5$$
2. $$120.0$$
3. $$222.0$$
4. $$119.0$$

Subtopic: Â Mass-Energy Equivalent |
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Which one of the following is incorrect?

 1 A chemical equation is balanced in the sense that the number of atoms of each element is the same on both sides of the equation. 2 The number of atoms of each element is not necessarily conserved in a nuclear reaction. 3 The number of protons and the number of neutrons are conserved in each nuclear reaction. 4 Mass-energy interconversion takes place only in nuclear reactions and never in the chemical reaction.

Subtopic: Â Nuclear Energy |
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If the mass of the iron nucleus is $$55.85~\text{u}$$ and $$\mathrm{A} = 56$$, the nuclear density of the iron is:
 1 $$2.27\times10^{17}~\text{kg m}^{-3}$$ 2 $$1.36\times 10^{15}~\text{kg m}^{-3}$$ 3 $$3.09\times10^{17}~\text{kg m}^{-3}$$ 4 $$4.11\times10^{15}~\text{kg m}^{-3}$$