Practice question

4 sides: r = 8m, 2 diagonals: r = 82m. V = −4Gm28−2Gm282. V = −6.67×10−11×64(48+282). V = −4.269×10−9(0.5+0.177)≈−2.89×10−9J. As per NCERT, applying relevant law/formula with correct units and sign convention leads to -2.9 × 10⁻⁹ J. This satisfies dimensional consistency and physical conditions given, so option B is scientifically correct.