6.1 The terminal voltages of various npn transistors are measured during operation in their respective circuits with the following results (in volts): Case 1 2 3 4 5 6 E oooo -0.7 -0.7 1.3 0 B 0.7 0.8 0 0 2.0 0 0.7 0.1 1.0 -0.6 5.0 5.0 Mode In this table, 0 indicates the reference terminal to which the black (negative) probe of the voltmeter is connected. For each case, identify the mode of operation of the transistor.