∵当S1断开S2闭合时,R0与Rx串联,电压表测电源电压
当S2断开S1闭合时,R0与Rx串联,电压表测Rx电压
∴Rx / R0 = Ux / U0
又∵U0 = U - Ux = 3 - 2.5 = 0.5v
∴代数得 Rx / 10 = 2.5 / 0.5
∴解得 Rx = 50Ω
∵当S1断开S2闭合时,R0与Rx串联,电压表测电源电压
当S2断开S1闭合时,R0与Rx串联,电压表测Rx电压
∴Rx / R0 = Ux / U0
又∵U0 = U - Ux = 3 - 2.5 = 0.5v
∴代数得 Rx / 10 = 2.5 / 0.5
∴解得 Rx = 50Ω