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Multiple choice physics nuclei nuclear force the nuclear force nuclear force and binding energy

Two nucleons are at a separation of one Fermi. Protons have a charge of $+1.6\times 10^{-19}$ C. The net nuclear force between them is $F _1$, if both are neutrons, $F _2$ if both are protons and $F _3$ if one is proton and the other is neutron. Then.

  1. $F _1 = F _2 >F _3$
  2. $F _1=F _2=F _3$
  3. $F _1< F _2 < F _3$
  4. $F _1 > F _2 > F _3$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Mass of proton = Mass of neutron = $1.67\times 10^{-27}Kg$
So, force between proton - proton, proton - neutron, neutron - neutron are equal.
So, $F _1=F _2=F _3$
Multiple choice physics nuclei nuclear force the nuclear force nuclear force and binding energy

A radioactive nucleus has specific binding energy '${E} _{1}$'. It emits an $\alpha$-particle. The resulting nucleus has specific binding energy '${E} _{2}$'. Then

  1. ${E} _{2}={E} _{1}$
  2. ${E} _{2}<{E} _{1}$
  3. ${E} _{2}>{E} _{1}$
  4. ${E} _{2}=0$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A radioactive nucleus always decays into more stable nucleus and high binding energy corresponds to more stable nucleus. Therefore, after emitting an alpha particle energy $E _2$ will be more than the initial energy $E _1$.

Multiple choice physics nuclei nuclear force the nuclear force nuclear force and binding energy

The nature of the electrostatic force and nuclear force between a proton and a neutron inside a nucleus are respectively.

  1. Repulsive and attractive

  2. Zero and attractive

  3. Repulsion and repulsive

  4. Attractive and attractive
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Since neutron is neutral in nature, the electrostatic force between neutron and proton is zero. They have attractive nuclear force between them which causes the nucleus to bind together. 

Multiple choice physics nuclei nuclear force the nuclear force nuclear force and binding energy

Range of nuclear force is approximately

  1. $2 \times 10^{-l5} m$
  2. $1.5 \times 10^{-20} m$
  3. $7.2 \times 10^{-4} m$
  4. $1.4 \times 10^{-15} m$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
The nuclear force is powerfully attractive between nucleons at distance of about 1 femtometre or $1.0\times{10}^{-15}$ metre, but it rapidly decreases to insignificance at distance beyond about 2.5fm
So, $(A)$ is correct.
Multiple choice physics nuclei nuclear force the nuclear force nuclear force and binding energy

Which of the following statements is wrong

  1. Strong nuclear forces are the strongest forces

  2. Nuclear forces are very short range forces

  3. nuclear force increases when the number of nucleons is increased

  4. None of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
There are four fundamental interactions account for all observed forces. These interactions are strong nuclear, electromagnetic, weak nuclear and gravitational
The strongest of these four is the strong nuclear. It is responsible for binding together the fundamental particles of matter to form larger particles.
However this interaction operates at a very short range inside the nucleus (as little as $1$fm- $1$ femo meter or ${ 10 }^{ -15 }$ meter)
Nuclear force is defined as the force exerted between numbers of nucleons. So nuclear force increases when the number of nucleons is increased. All statements are correct.
Multiple choice physics nuclei nuclear force the nuclear force nuclear force and binding energy

The force between protons in the nucleus will b

  1. only nuclear

  2. only coulomb

  3. nuclear & coulomb

  4. coulomb & gravitational
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
The electrostatic force between an electron and a proton is given by Coulombs Law of force, that is directly proportional; to the product of charges of electron and the proton and inversely proportional to the square of distance between the two particles
Another force on proton is nuclear force as it the force exerted between numbers of nucleons. This force is attractive in nature which binds protons and neutrons in the nucleus together.
Multiple choice physics nuclei nuclear force the nuclear force nuclear force and binding energy

If the ionization energy of hydrogen atom is $13.6 eV$ then the wavelength of the radiation required to excite the electron in $L{ i }^{ ++ }$ from first to third Bohr orbit is approximately

  1. $1140 A$
  2. $914 A$
  3. $11.4 A$
  4. $134 A$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Ionisation energy is given by

$E = 13.6\ eV$ (given)
or $E = 13.6 \times 1.6 \times 10^{-19} J ....(1)$
also $E = hv$
$E = \dfrac{hc}{\lambda} ....(2)$
equation $(1)$ and $(2)$
$\dfrac{hc}{\lambda} = 13.6 \times 1.6 \times 10^{-19}$
$\lambda = \dfrac{h \times c}{13.6 \times 1.6 \times 10^{-19}}$
$\lambda = \dfrac{3 \times 10^{8} \times 6.63 \times 10^{-34}}{13.6 \times 1.6 \times 10^{-19}}$
$\lambda = 914 \times 10^{-10} m$
$\lambda = 914 A^o$

Multiple choice physics nuclei nuclear force the nuclear force nuclear force and binding energy

Mass numbers of the elements A, B, C and D are 30, 60, 90 and 120 respectively. the  specific binding energy of them are 5 MeV, 8.5 MeV, 8 MeV and 7 MeV respectively. then, in which of the following reaction/s energy is released?
(1) $ D \rightarrow 2B $
(2) $ C \rightarrow B+A $
(3) $ B \rightarrow 2A $

  1. only in (1)

  2. in(2), (3)

  3. in (1), (3)

  4. in (1), (2) and (3)
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Energy is released when the product has a higher specific binding energy than the reactants. (1) D(7 MeV) -> 2B(8.5 MeV): 8.5 > 7, so energy is released. (2) C(8 MeV) -> B(8.5 MeV) + A(5 MeV): Average BE is (8.5+5)/2 = 6.75 < 8, so energy is absorbed. (3) B(8.5 MeV) -> 2A(5 MeV): 5 < 8.5, so energy is absorbed.

Multiple choice physics nuclei nuclear force the nuclear force nuclear force and binding energy

If $F _{NN}$, $F _{NP}$, $F _{PP}$ denotes net force between neutron and neutron, neutron and proton, proton and proton then

  1. $F _{NN}$ = $F _{NP}$ = $F _{PP}$
  2. $F _{NN}$ = $F _{NP}$ > $F _{PP}$
  3. $F _{NN}$ = $F _{NP}$ < $F _{PP}$
  4. $F _{NN}$ >$F _{NP}$>$F _{PP}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

At separation less than one fermi, hence nuclear force of attraction is strongly active.
Nuclear force is charge independent force.
So, $F _{pp} = F _{pn} = F _{nn}$