Умоляю помогите!!SOS!!!

1) U=I*R=30*0.25=7.5 B2)R=po*L/S=1.1*40/0.5=88 Ом3) R=0.023*1.5/0.1=0.345 ОмU=I*R=0.5*0.345=0.17 В===========