किस नेटवर्क प्रमेय के लिए रैखिकता (linearity) का कड़ाई से पालन होना आवश्यक है, लेकिन तत्वों की द्विपक्षीय (bilateral) प्रकृति अनिवार्य नहीं है?

While calculating Thevenin resistance (Rth) or Norton resistance (RN), independent constant current sources in the circuit are:

While calculating Thevenin resistance (Rth), constant current sources in the circuit are:

According to the Maximum Power Transfer Theorem, maximum power is delivered from a source to a load when the load resistance (RL) is equal to the internal resistance (r) of the source. At this specific condition, what is the efficiency of the power transfer?