Tag: nuclei

Questions Related to nuclei

Using $E = m{c}^{2}$, find out the energy released, when $2  u$ of mass is destroyed completely.
Take $1  u = 1.66 \times {10}^{-27}  kg$.

nuclear reactions nuclear structure nuclei atomic nuclei physics

  1. $4.65 MeV$

  2. $3627 MeV$

  3. $91.5 MeV$

  4. $1865 MeV$

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Correct Option: D
Explanation:
When $2u$ of mass is destroyed completely then
$\triangle m=2u\\ E=\triangle m{ c }^{ 2 }\\ E=2\times 931MeV\\ \therefore 1u=931Mev/{ c }^{ 2 }\\ So,E=1863MeV\approx 1865MeV$
So, (D) is correct option.
What  describe the Einsteins equation for the relativity of mass and energy ?
nuclear reactions nuclear structure nuclei atomic nuclei physics

  1. a small amount of mass contains a lot of energy.

  2. a small amount of energy can be converted into a large amount of mass.

  3. a small amount of mass contains a small amount of energy.

  4. mass can be converted into energy, but energy cannot be converted mass.

  5. energy can be converted into mass, but mass cannot be converted into energy.

Show answer
Correct Option: A
Explanation:

Sir Einstein's mass-energy equation states that mass and energy can be converted into each other by the following relation.

                 $E=mc^{2}$,    ($c=$speed of light)
This implies that a small amount of mass contains a lot of energy, which can be proved with an example.
Let we have a mass of $1g=10^{-3}kg$ , therefore energy produced by it will be:
                      $E=10^{-3}\times \left(3\times10^{8}\right)^{2}=9\times10^{13}J$ 
which is a vast amount energy produced by only one gram (small mass) of mass.
Whereas a small amount of energy doesn't give a large amount of mass because for that we have to divide the energy by $c^{2}$, which gives a small mass.

Find the accurate expressions.
nuclear reactions nuclear structure nuclei atomic nuclei physics

  1. $E = mc^2$

  2. $E = m/c^2$

  3. $M = Ec^2$

  4. All of the expressions are accurate.

  5. $c = Em^2$

Show answer
Correct Option: A
Explanation:

Before Sir Einstien, mass and energy were two completely different physical quantities, which were not related to each other anyway. Sir Einstein told that energy and mass are related to each other i.e. energy and mass can be converted into each other by the following relation:

      $E=mc^{2}$, called Sir Einstein's mass-energy equivalence

Which of the following statement is accurate for an object approaching the speed of light ?
nuclear reactions nuclear structure nuclei atomic nuclei physics

  1. The particle's mass will increase as it approaches the speed of light.

  2. The particle's mass will increase as it approaches, and then decrease when it reaches the speed of light.

  3. The particle's mass will decrease as it approaches the speed of light.

  4. The particle's dimensions will increase but it's mass will remain constant as it approaches the speed of light.

  5. All of the statements are accurate

Show answer
Correct Option: A
Explanation:

The mass of object as observed by a moving observer is given by $m=\dfrac{m _0}{\sqrt{1-(\dfrac{v}{c})^2}}$.

where $m _0$ is the rest mass of the object.

Hence, as speed approaches the speed of light, that is, as $v\rightarrow c$, $m\rightarrow \infty$

The rest energy involved in a mass of one atomic mass unit is _________ eV.

nuclear reactions nuclear structure nuclei atomic nuclei physics

  1. $931$ MeV

  2. $1.6$ eV

  3. $9.3$ MeV

  4. $9.1$

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Correct Option: A
Explanation:

931 MeV

The mass of 1 amu is equivalent to an energy of 931 MeV. 

The unit of rate constant for a zero order reaction is:

nuclear reactions nuclear structure nuclei atomic nuclei physics

  1. $s^{-1}$

  2. $mol L^{-1}s^{-1}$

  3. $L mol ^{-1}s^{-1}$

  4. $L^{2} mol ^{-2}s^{-1}$

Show answer
Correct Option: B
Explanation:
For zero order reaction
Rate $=K[A]^0$
Rate $=K=\cfrac{d[A]}{dt}$
Unit of rate constant $=Unit\; of \; \cfrac{d[A]}{dt} \\=\cfrac{mol L^{-1}}{sec} \\=mol L^{-1} sec^{-1}$

Which of the following assertions are correct?

nuclear reactions nuclear structure nuclei atomic nuclei physics

  1. A neutron can decay to a proton only inside a nucleus

  2. A proton can change to a neutron only inside a nucleus

  3. An isolated neutron can change into proton

  4. An isolated proton can change into a neutron

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Correct Option: B

Inside nucleus, protons are held together though they have the dame charge. Why?

nuclear reactions nuclear structure nuclei atomic nuclei physics

  1. The strong attractive nuclear force far exceeds the electrostatic force between the protons

  2. Neutrons prevent them from repelling from each other

  3. The electrostatic attractive force between an electron and a proton is more than the electrostatic repulsive force between the protons

  4. Gluons are responsible for holding them together

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Correct Option: A

The conversion of 1 u of mass results in ________ eV of energy.

nuclear reactions nuclear structure nuclei atomic nuclei physics

  1. $9.315 \times 10^6$

  2. $391.5 \times 10^6$

  3. $931.5 \times 10^6$

  4. $93.15 \times 10^6$

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Correct Option: C

Magnitude of mass defect is a measure of ......................... of a nucleus.

nuclear reactions nuclear structure nuclei atomic nuclei physics

  1. Unstability

  2. Stability

  3. Charge

  4. Position

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Correct Option: B