Define ionisation energy.
How would the ionisation energy change when electron in hydrogen atom is replaced by a particle of mass 200 times that of the electron but having the same charge ?
The minimum energy, required to free the electron from the ground state of the hydrogen atom, is known as ionization energy.
Ionisation energy is given by,
Since, ionisation energy is directly proportional to mass, the Ionization energy will become 200 times.
The B.E. of the nucleus of mass number 240, B1 = 7.6 x 240 = 1824 MeV
The B.E of each product nucleus, B2 = 8.5 x 120 - 1020 MeV
Then, the energy released as the nucleus breaks is given by,
E = 2B2 - B1 = 2 x 1020 - 1824 = 216 MeV
OR
Given:
B.E of 
B.E of 
Energy in the fusion reaction is given by, 
Using the curve for the binding energy per nucleon as a function of mass number A, state clearly how the release in energy in the processes of nuclear fission and nuclear fusion can be explained.
The binding energy per nucleon increases when a heavy nucleus breaks into two lighter nuclei. That is, energy would be released during the process of nuclear fusion.
When light nuclei join to form a heavy nucleus, the binding energy per nucleon of fused heavier nucleus is more than the binding energy per nucleon of lighter nuclei. Again, there is release of energy in this processDraw a plot of potential energy of a pair of nucleons as a function of their separations. Mark the regions where the nuclear force is (i) attractive and (ii) repulsive. Write any two characteristic features of nuclear forces.
The below figure shows the plot of potential energy of a pair of nucleons as a function of their separation.
AB represents repulsive force and part BCD reprtesents attractive force.
Properties of nuclear forces are:
(1) Nuclear forces are attractive and stronger, then electrostatic force.
(2) Nuclear forces are charge-independent.
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