Multiple choice general knowledge How many Ergs are these in 1 Joule? 102 104 106 107 Reveal answer Fill a bubble to check yourself D Correct answer Explanation One joule equals 10^7 ergs because joule uses kg-m-s units while erg uses g-cm-s units. Converting kg to g (1000) and m to cm (100): 1 J = 1 kg × 1 m²/s² = 1000 g × 10000 cm²/s² = 10^7 erg.