Nuclei · Question 2

List-I shows various functional dependencies of energy (E) on the atomic number (Z). Energies associated with certain phenomena are given in List-II. Choose the option that describes the correct match between the entries in List-I to those in List-II.

1. P → 4, Q → 3, R → 1, S → 2
2. P → 5, Q → 2, R → 1, S → 4
3. P → 5, Q → 1, R → 2, S → 4
4. P → 3, Q → 2, R → 1, S → 5

Answer

(3) P → 5, Q → 1, R → 2, S → 4

Solution

(P) Hydrogen-like atoms: En Z2n2, so transition energies Z2 → 5

(Q) Moseley's law for characteristic (K ) x-rays: E (Z-1)2 → 1

(R) Coulomb repulsion among Z protons: number of proton pairs = Z(Z-1)2, so electrostatic energy Z(Z-1) → 2

(S) Binding energy per nucleon is nearly constant ( 8 MeV) for A=30 to 170 → 4

(Continuous x-ray energy depends on accelerating voltage, not on Z in these forms.)

Answer: (C)