Final answer:
Tech A is correct about the series circuit, with the total resistance being 240 ohms. Tech B, however, is incorrect regarding the parallel circuit, where the correct total resistance is 60 ohms, not 240 ohms.
Step-by-step explanation:
Tech A is correct in stating that in a series circuit with two resistors of 120 ohms each, the total circuit resistance is 240 ohms. This is because in a series connection, resistances add up directly. Therefore, R_total = R1 + R2, which in this case equals 120 ohms + 120 ohms = 240 ohms.
On the other hand, Tech B is incorrect. In a parallel circuit, the total resistance is not the sum of the individual resistances. Instead, the inverse total resistance is the sum of the inverses of each individual resistance. For two resistors of 120 ohms each in parallel, the total resistance R_total can be calculated using 1/R_total = 1/R1 + 1/R2, resulting in 1/R_total = 1/120 + 1/120, which simplifies to 1/R_total = 2/120 or R_total = 60 ohms.
Therefore, for the parallel case, the correct total resistance would be 60 ohms, not 240 ohms. It is important to apply the correct rules for calculating resistance based on the type of circuit configuration.