Q18. The energy equivalent of 1 g of substance is :\\ (1) $5.6 \times 10 ^ { 12 } \mathrm { MeV }$\\ (2) $5.6 \times 10 ^ { 26 } \mathrm { MeV }$\\ (3) $11.2 \times 10 ^ { 24 } \mathrm { MeV }$\\ (4) 5.6 eV