某水泵運(yùn)行時(shí)進(jìn)口壓力為0.05Mpa,排出口壓力為0.25Mpa,則水泵的壓頭為()。
A.20mH2O B.25mH2O C.30mH2O D.35mH2O
A.2m B.7m C.12m D.都不對(duì)
A.4m B.55m C.55.4m D.60.5m