On resistors with four colour bands, which colour band differentiates two resistors rated at 120 ohms and 1200 ohms respectively?

On a standard four-band resistor, the first two colour bands represent the significant digits of the resistor's value. For both 120 ohms and 1200 ohms, the significant digits are 1 and 2 (which correspond to the colours Brown and Red). The third band represents the multiplier, indicating the number of trailing zeros to add after the first two digits. For 120 ohms, you need one zero (a multiplier of 10, represented by Brown), while for 1200 ohms, you need two zeros (a multiplier of 100, represented by Red). Therefore, it is the third colour band that differentiates these two specific values. The fourth band dictates the tolerance (margin of error) and does not change the nominal base value.