Suatu lampu pijar ditandai 220V-40W maka hambatan listrik lampu kira kira

diket :
P = 40 w
V = 220 v
dit : Hambatan
jwb :
R = V^2 /P
R = 220^2 / 40
R = 48.400 / 40
R = 1210 ohm = 1,21 k ohm