What do the color bands on a resistor represent?

• A. They indicate the color temperature of the resistor
• B. They encode the resistance value and multiplier
• C. They show the resistor's power rating
• D. They indicate manufacturer and lot number

Answer: (B)

Color bands on a resistor form a code that represents its numerical resistance value and the multiplier used to scale that value. In the common four-band scheme, the first two bands give the significant digits, the third band is the multiplier (a power of ten that scales the digits), and the fourth band indicates tolerance. For example, a resistor with bands that read brown, black, red, and gold represents 10 × 10^2 ohms, which is 1 kilohm, with a tolerance of about ±5%. Some resistors use a five-band code where three digits are shown before the multiplier, and a sixth band can indicate temperature coefficient. The key idea is that the color sequence translates into a numeric resistance value and how precisely that value is known.

Other properties like color temperature, power rating, or manufacturer/lot information aren’t conveyed by the color bands, which is why those choices don’t fit.