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Outside a nucleus

Neutron is stable

Proton and neutron both are stable

Neutron is unstable

Neither neutron nor proton is stable

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Explanation

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Order of magnitude of density of uranium nucleus is ( $m_{P} = 1.67 \times 10^{- 27} kg$ )

$10^{20} kg / m^{3}$

$10^{17} kg / m^{3}$

$10^{14} kg / m^{3}$

$10^{11} kg / m^{3}$

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Explanation

(b) The order of magnitude of mass and volume of uranium nucleus will be
m â‰ƒ A( $1.67 \times 10^{- 27}$ kg) (A is atomic number)
$V = \frac{4}{3} {πr}^{3} ≃ \frac{4}{3} π {[(1.25 \times 10^{- 15} m) A^{1 / 3}]}^{3} ≃ (8.2 \times 10^{- 45} m^{3}) A$

Hence, $ρ = \frac{m}{V} = \frac{A (1.67 \times 10^{- 27} kg)}{(8.2 \times 10^{- 45} m^{3}) A}$

$≃ 2.0 \times 10^{17} kg / m^{3}$
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Radius of ${}_{2}^{4}{He}$ nucleus is 3 Fermi. The radius of ${}_{82}^{206}{Pb}$ nucleus will be

5 Fermi

6 Fermi

11.16 Fermi

8 Fermi

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Explanation

(c) We have $r \propto A^{1 / 3} \Rightarrow \frac{r_{2}}{r_{1}} = {(\frac{A_{2}}{A_{1}})}^{1 / 3} = {(\frac{206}{4})}^{1 / 3}$

$∴ r_{2} = 3 {(\frac{206}{4})}^{1 / 3} = 11.16 Fermi$

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Nucleus of an atom whose atomic mass is 24 consists of

11 electrons, 11 protons and 13 neutrons

11 electrons, 13 protons and 11 neutrons

11 protons and 13 neutrons

11 protons and 13 electrons

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Explanation

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The mass of a neutron is the same as that of

A proton

A meson

An epsilon

An electron

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Explanation

(a) Mass of proton and neutron is lame.

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The mass defect per nucleon is called

Binding energy

Packing fraction

Ionisation energy

Excitation energy

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Explanation

(b)

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Nuclear forces are

Short ranged attractive and charge independent

Short ranged attractive and charge dependent

Long ranged repulsive and charge independent

Long ranged repulsive and charge dependent

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Explanation

(a) Nuclear force is charge independent, it also acts between two neutrons.

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Antiparticle of electron is

${}_{0}n_{1}$

${}_{1}H_{1}$

Positron

Neutrino

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Explanation

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The binding energy per nucleon is maximum in the case of

${}_{4}^{2}{He}$

${}_{26}^{56}{Fe}$

${}_{56}^{141}{Ba}$

${}_{92}^{235}U$

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Explanation

The binding energy per nucleon is maximum for nuclei with mass number around 60, such as iron (Fe-56). This is because the strong nuclear force, which binds the nucleons together, is most effective at this mass range, resulting in a higher binding energy per nucleon.

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Isotopes are atoms having

Same number of protons but different number of neutrons

Same number of neutrons but different number of protons

Same number of protons and neutrons

None of the above

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Explanation

(a) For isotopes Z is same and A is different. Therefore the number of neutrons A-Z will also be different.

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