Four statements about nuclear volume and mass defect are given (A denotes mass number): A. Nuclear volume is proportional to A¹ᐟ³. B. Nuclear volume is proportional to A. C. Atom mass minus nucleus mass is called mass defect. D. The difference between the summed free constituent masses and the mass of the bound nucleus is the mass defect. Select the true statements.
Options

Question

Four statements about nuclear volume and mass defect are given (A denotes mass number): A. Nuclear volume is proportional to A¹ᐟ³. B. Nuclear volume is proportional to A. C. Atom mass minus nucleus mass is called mass defect. D. The difference between the summed free constituent masses and the mass of the bound nucleus is the mass defect. Select the true statements.

Options

G1 Physics · Accepted Answer

Step 1: Nuclear radius R = R₀A¹ᐟ³. Hence volume V = (4π/3)R³ ∝ (A¹ᐟ³)³ = A. So A is false and B true. Step 2: Atom mass minus nucleus mass is mainly the mass of electrons (with small binding corrections). That difference is not the nuclear mass defect; C is false. Step 3: Nuclear mass defect Δm = Zmₚ + (A − Z)mₙ − M(nucleus). Therefore statement D is true. Final answer: B and D are true (Option B).