Diketahui efisien 60% dan WS 300 joule,brapa WP pada trafo??

diket :
ef = 60%
Ws = 300 j
dit : Energi primer
jwb :
ef = ( Ws / Wp ) .100 %
60% = ( 300 / Wp ) .100 %
Wp = ( 300 / 60 ) . 100
Wp = 5 . 100
Wp = 500 j