Q: What is the wavelength of a photon emitted during a transition from \$n = 5\$ state to \$n = 2\$ state in the hydrogen atom?

\$\displaystyle \dfrac { 1}{ \lambda }=R [\dfrac { 1 }{n^2_1 } - \dfrac { 1}{ n^2_2 }] \$\$\displaystyle \dfrac { 1}{ \lambda }=109677.6 \ cm^{-1} \times [\dfrac { 1 }{2^2 } - \dfrac { 1}{ 5^2 }]\$\$\displaystyle \dfrac { 1}{ \lambda }=23032.3 \ cm^{-1} \$\$\displaystyle \lambda = 4.34 \times 10^{-5} \ cm\$Convert unit from cm to nm1 cm \$\displaystyle =10^7 \ nm\$\$\displaystyle \lambda = 4.34 \times 10^{-5} \ cm \times \dfrac {10^7 \ nm}{ 1 \ cm}\$\$\displaystyle \lambda = 434 \ nm\$

Q: The energy equivalent of \$0.5 g\$ of a substance is :

The energy equivalent of the particular mass is given as:\$E=mc^2\$mass is given as \$=0.5g=0.5\times 10^{-3}\ kg\$and the speed of light \$(c)=3\times 10^8\ m/s\$;.So, \$E=0.5\times10^{-3}\times(3\times 10^{8})^2\$\$E=4.5\times 10^{!3}\ J\$

Q: The energy equivalent to a substance of mass \$1\$g is?

\$E=mC^2\$\$=1\times 10^{-3}\times 9\times 10^{16}\$\$=9\times 10^{13}\$J

Q: The energy equivalent of \$1\ amu\$ is

\$1\ amu =1.66\times 10^{-27} kg\$According to Einstein's mass energy equivalence, \$E=mc^2\$ where \$c=\$ velocity of light. So, \$E=1.66\times 10^{-27}\times (3\times 10^8)^2=14.94\times 10^{-11} J\$\$E=\dfrac{14.94\times 10^{-11}}{1.6\times 10^{-19}} eV\$ where \$1eV=1.6\times 10^{-19} J\$\$E=931\times 10^{6} eV=931\ MeV\$

Q: When a uranium isotope \$^{235}_{92}U\$ is bombarded with a neutron, it generates \$^{89}_{36}Kr\$, three neutrons and :

\$_{92}U^{235} + \ _on^1 \to \ _QX^P + _{36}Kr^{89} + 3\ _on^1+ Q(energy)\$\$\sum\$ Atomic number on \$LHS = 89 + 0 = 89 + 3\$\$\sum\$ Atomic number on \$RHS = Q + 36 + 3 \times 0\$\$\therefore LHS = RHS\$\$Q+36 = 92\$\$Q = 56\$also, \$\sum\$ atomic mass number on \$LHS = 235 + 1 = 236\$\$\sum\$ Atomic mass number on \$RHS=P + 89 + 3 \times 1\$\$\therefore LHS = RHS\$\$P + 92= 236\$\$P = 144\$So, the element is \$_{56}Ba^{144}\$

Q: In nuclear fission, \$0.1\%\$ mass is converted into energy. The energy released in the fission of \$1\$Kg mass in KWH is

\$0.\$1% Mass is converted.\$E = (\dfrac{1}{1000}\times 1 kg)(3\times 10^8)^2 J\$ \$= 9\times 10^{13} J\$Let this energy is librated per second then,\$E\$ per hour \$= \dfrac{9\times 10^{13}}{60\times 60}\$\$= 0.25\times 10^{11} WH\$\$= 2.5\times 10^7 KWH\$

Q: One milligram of matter is converted into energy. The energy released will be

Here, \$m = 1\ mg = 1\times 10^{-3} g \$ \$= 1\times 10^{-6}kg\$According to Einstein mass-energy equivalence \$E = mc^{2}\$where \$c\$ is the speed of light in vacuum\$\therefore E = (1\times 10^{-6} kg)(3\times 10^{8}ms^{-1})^{2}\$\$ = 9\times 10^{10}J\$.

Q: The mass defect in a particular nuclear reaction in 0.3 grams.The amount of energy liberated in kilowatt hour is \$\left( Velocity\ of \ light=3\times { 10 }^{ 8 }m/s \right) \$

Mass defect in a nuclear reaction \$\Delta M = 0.3 g = 3 \times 10^{-4} kg\$Thus amount of energy released \$E = \Delta M c^2 = (3 \times 10^{-4}) \times (3 \times 10^8)^2 J\$\$\implies E = 27 \times 10^{12} J (1 kWh = 3.6 \times 10^6 J)\$\$\therefore E = 7.5 \times 10^{6} kWh \$

Question 1

What is the wavelength of a photon emitted during a transition from $n = 5$ state to $n = 2$ state in the hydrogen atom?

Accepted Answer

$\displaystyle  \dfrac {  1}{ \lambda }=R [\dfrac {  1 }{n^2_1  } - \dfrac {  1}{ n^2_2 }] $$\displaystyle  \dfrac {  1}{ \lambda }=109677.6 \ cm^{-1} \times  [\dfrac {  1 }{2^2  } - \dfrac {  1}{ 5^2 }]$$\displaystyle  \dfrac {  1}{ \lambda }=23032.3 \ cm^{-1} $$\displaystyle \lambda = 4.34 \times 10^{-5} \ cm$Convert unit from cm to nm1 cm $\displaystyle =10^7 \ nm$$\displaystyle \lambda = 4.34 \times 10^{-5} \ cm \times  \dfrac {10^7 \ nm}{ 1 \ cm}$$\displaystyle \lambda = 434  \ nm$

Question 2

The energy equivalent of $0.5 g$ of a substance is :

Accepted Answer

The energy equivalent of the particular mass is given as:$E=mc^2$mass is given as $=0.5g=0.5\times 10^{-3}\ kg$and the speed of light $(c)=3\times 10^8\ m/s$;.So, $E=0.5\times10^{-3}\times(3\times 10^{8})^2$$E=4.5\times 10^{!3}\ J$

Question 3

The energy equivalent to a substance of mass $1$g is?

Accepted Answer

$E=mC^2$$=1\times 10^{-3}\times 9\times 10^{16}$$=9\times 10^{13}$J

Question 4

The energy equivalent of $1\ amu$ is

Accepted Answer

$1\ amu =1.66\times 10^{-27} kg$According to Einstein's mass energy equivalence, $E=mc^2$ where $c=$ velocity of light. So, $E=1.66\times 10^{-27}\times (3\times 10^8)^2=14.94\times 10^{-11} J$$E=\dfrac{14.94\times 10^{-11}}{1.6\times 10^{-19}} eV$       where $1eV=1.6\times 10^{-19} J$$E=931\times 10^{6} eV=931\ MeV$

Question 5

When a uranium isotope $^{235}_{92}U$ is bombarded with a neutron, it generates $^{89}_{36}Kr$, three neutrons and :

Accepted Answer

$_{92}U^{235} + \ _on^1 \to \ _QX^P + _{36}Kr^{89} + 3\ _on^1+ Q(energy)$$\sum$ Atomic number on $LHS = 89 + 0 = 89 + 3$$\sum$ Atomic number on $RHS = Q + 36 + 3 \times 0$$\therefore LHS = RHS$$Q+36 = 92$$Q = 56$also, $\sum$ atomic mass number on $LHS = 235 + 1 = 236$$\sum$ Atomic mass number on $RHS=P + 89 + 3 \times 1$$\therefore LHS = RHS$$P + 92= 236$$P = 144$So, the element is $_{56}Ba^{144}$

Question 6

If both the number of protons and the number of neutrons are conserved in each nuclear reaction in what way is mass converted into energy (or vice-versa) in a nuclear reaction?

Accepted Answer

The sum of masses of nuclei of product element is less than sum of masses of reactants and hence, loss of mass takes place during the reaction. This difference of mass of product element and reactant converts into energy and liberated in the form of heat.$H^2_1$ +$H^2_1$&#8594; $H^3_2 $+ $n^2_1$ + $energy$

Question 7

In nuclear fission, $0.1\%$ mass is converted into energy. The energy released in the fission of $1$Kg mass in KWH is

Accepted Answer

$0.$1% Mass is converted.$E = (\dfrac{1}{1000}\times 1 kg)(3\times 10^8)^2 J$    $= 9\times 10^{13} J$Let this energy is librated per second then,$E$ per hour $= \dfrac{9\times 10^{13}}{60\times 60}$$= 0.25\times 10^{11} WH$$= 2.5\times 10^7 KWH$

Question 8

One milligram of matter is converted into energy. The energy released will be

Accepted Answer

Here, $m = 1\ mg = 1\times 10^{-3} g $             $= 1\times 10^{-6}kg$According to Einstein mass-energy equivalence                $E = mc^{2}$where $c$ is the speed of light in vacuum$\therefore E = (1\times 10^{-6} kg)(3\times 10^{8}ms^{-1})^{2}$$ = 9\times 10^{10}J$.

Question 9

The mass defect in a particular nuclear reaction in 0.3 grams.The amount of energy liberated in kilowatt hour is $\left( Velocity\ of \  light=3\times { 10 }^{ 8 }m/s \right) $

Accepted Answer

Mass defect in a nuclear reaction          $\Delta M = 0.3    g  =  3 \times 10^{-4}    kg$Thus amount of energy released        $E = \Delta M    c^2  =  (3 \times 10^{-4}) \times (3 \times 10^8)^2           J$$\implies         E =  27  \times 10^{12}      J                                  (1   kWh = 3.6  \times 10^6    J)$$\therefore         E  = 7.5   \times 10^{6}     kWh $

Question 10

What does mean by mass defect? Establish relation between mass defect and nuclear binding energy. And hence write the expression for binding energy per nucleon.

Accepted Answer

Mass defect: It is found that mass of a stable nucleus is alway less than the sum of masses of its constituent protons and neutrons in their free state. Consider the Nucleus $^A_ZX$. It has Z protons (A-Z) neutrons, therefore its mass defect will be $\Delta m=Zm_p+(A-Z)m_n-m$Expression for binding energy: The nucleus $^A_ZX$ contains Z protons and $(A-Z)$ neutrons.Its mass defect is    $\Delta  m =Zm_p+(A-Z)m_n-m_N$Where $m_N \rightarrow$ mass of nucleus   $\Delta E_b=\Delta  m \times c^2=[Zm_p+(A-Z)m_n-m_N]c^2$Mass defect always improve binding energy of nucleus. For mass defect is more stable nucleus.

Revise with Concepts

Problems on Nuclear Structure and Reactions

Mass - Energy Relation of Nuclei

Pair Production and Pair Animation

Nuclear Reactions -Medium

Quick Summary With Stories

Disintegration Energy and Conservation of Energy in Nuclear Reactions

Nuclear Reactions

Nuclear Weapons

Difference between Chemical and Atomic Change

Differences between Chemical Reactions and Nuclear Reactions

Difference in Emission of particles and energy during a chemical and a nuclear reaction

Balanced Equations

Mass - Energy Relation of Nuclei

Pair Production and Pair Animation

Nuclear Energy

What is the wavelength of a photon emitted during a transition from $n = 5$ state to $n = 2$ state in the hydrogen atom?

The energy equivalent of $0.5 g$ of a substance is :

The energy equivalent to a substance of mass $1$ g is?

The energy equivalent of $1 a m u$ is

When a uranium isotope $_{92}^{235} U$ is bombarded with a neutron, it generates $_{36}^{89} K r$ , three neutrons and :

If both the number of protons and the number of neutrons are conserved in each nuclear reaction in what way is mass converted into energy (or vice-versa) in a nuclear reaction?

In nuclear fission, $0.1 %$ mass is converted into energy. The energy released in the fission of $1$ Kg mass in KWH is

One milligram of matter is converted into energy. The energy released will be

The mass defect in a particular nuclear reaction in 0.3 grams.The amount of energy liberated in kilowatt hour is $(V e l o c i t y o f l i g h t = 3 \times 10^{8} m / s)$

What does mean by mass defect? Establish relation between mass defect and nuclear binding energy. And hence write the expression for binding energy per nucleon.

Revise with Concepts

Problems on Nuclear Structure and Reactions

Mass - Energy Relation of Nuclei

Pair Production and Pair Animation

Nuclear Reactions -Medium

Quick Summary With Stories

Disintegration Energy and Conservation of Energy in Nuclear Reactions

Nuclear Reactions

Nuclear Weapons

Difference between Chemical and Atomic Change

Differences between Chemical Reactions and Nuclear Reactions

Difference in Emission of particles and energy during a chemical and a nuclear reaction

Balanced Equations

Mass - Energy Relation of Nuclei

Pair Production and Pair Animation

Nuclear Energy

What is the wavelength of a photon emitted during a transition from n=5 state to n=2 state in the hydrogen atom?

The energy equivalent of 0.5g of a substance is :

The energy equivalent to a substance of mass 1g is?

The energy equivalent of 1 amu is

When a uranium isotope 92235​U is bombarded with a neutron, it generates 3689​Kr, three neutrons and :

If both the number of protons and the number of neutrons are conserved in each nuclear reaction in what way is mass converted into energy (or vice-versa) in a nuclear reaction?

In nuclear fission, 0.1% mass is converted into energy. The energy released in the fission of 1Kg mass in KWH is

One milligram of matter is converted into energy. The energy released will be

The mass defect in a particular nuclear reaction in 0.3 grams.The amount of energy liberated in kilowatt hour is (Velocity of light=3×108m/s)

What does mean by mass defect? Establish relation between mass defect and nuclear binding energy. And hence write the expression for binding energy per nucleon.

What is the wavelength of a photon emitted during a transition from $n = 5$ state to $n = 2$ state in the hydrogen atom?

The energy equivalent of $0.5 g$ of a substance is :

The energy equivalent to a substance of mass $1$ g is?

The energy equivalent of $1 a m u$ is

When a uranium isotope $_{92}^{235} U$ is bombarded with a neutron, it generates $_{36}^{89} K r$ , three neutrons and :

In nuclear fission, $0.1 %$ mass is converted into energy. The energy released in the fission of $1$ Kg mass in KWH is

The mass defect in a particular nuclear reaction in 0.3 grams.The amount of energy liberated in kilowatt hour is $(V e l o c i t y o f l i g h t = 3 \times 10^{8} m / s)$