# Physics Class 12 NCERT Solutions: Chapter 13 Nuclei Part 2

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Q: 4. Obtain the binding energy of the nuclei and in units of from the following data:

Atomic mass of

Nucleus has protons and neutrons

Hence, the mass defect of the nucleus,

Where,

But

The binding energy of this nucleus is given as:

Where,

Speed of light

Average binding energy per nucleon

Atomic mass of

Nucleus has protons and neutrons.

Hence, the mass defect of this nucleus is given as:

Where,

Mass of a proton,

Mass of a neutron,

But

Hence, the binding energy of this nucleus is given as:

Average binding energy per nucleon

Q: 5. A given coin has a mass of. Calculate the nuclear energy that would be required to separate all the neutrons and protons from each other. For simplicity assume that the coin is entirely made of atoms.

Mass of a copper coin,

Atomic mass of atom,

The total number of atoms in the coin

Where,

Mass number

Nucleus has protons and neutrons

∴Mass defect of this nucleus,

Where,

Mass of a proton,

Mass of a neutron,

Mass defect of all the atoms present in the coin,

But

Hence, the binding energy of the nuclei of the coin is given as:

But

This much energy is required to separate all the neutrons and protons from the given coin.