Final answer:
To achieve a total resistance of 1 ohm, in series, resistors summing to 1 ohm are used, while in parallel, an arrangement like two 2 ohm resistors in parallel is needed. The principle behind this is exemplified by Ohm's law, V = IR.
Step-by-step explanation:
The question pertaining to the resistance needed to 'make 1' is likely referring to achieving a total resistance of 1 ohm in a circuit. In physics, specifically when studying electricity, resistance is measured in ohms (Ω), and is related to volts and amperes by the formula 1 Ω = 1 volt per ampere (V/A). When resistors are connected in a circuit, the total resistance can change depending on whether they are in series or parallel.
In series, resistances simply add together, so to achieve a total resistance of 1 Ω, you could combine several resistors whose resistances sum to 1 Ω. For example, two 0.5 Ω resistors in series would give you 1 Ω. If dealing with parallel resistors, however, the calculation is different as you must take the reciprocal of the sum of the reciprocals of each resistance. To achieve a total of 1 Ω in parallel, you could use two 2 Ω resistors since 1/Rp = 1/2 Ω + 1/2 Ω = 1 Ω.
Understanding the relationship between current (I), voltage (V), and resistance (R) is crucial, as described by Ohm's law, V = IR. This means that the voltage drop across a resistor can be found by multiplying the current flowing through it by its resistance. Resistance values can vary greatly across different materials and applications, from insulators like ceramic with resistances over 1012 Ω, to conductors like copper wire which may have resistances as low as 10-5 Ω.