Practice question

ΔE = −GMEm(1r2−1r1). r1 = 6.4×107m, r2 = 1.28×108m. ΔE = −6.67×10−11×6×1024×600(11.28×108−16.4×107). ΔE = −2.401×1017(−7.8125×10−9)≈1.88×109J. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 1.9 × 10⁹ J. This satisfies dimensional consistency and physical conditions given, so option B is scientifically correct.