A resistor has color bands red, yellow, and orange in that order. What is its resistance in ohms?

• A. 2400 ohms
• B. 240000 ohms
• C. 2400000 ohms
• D. 24000 ohms

Answer: (D)

Reading resistor color bands means two digits followed by a multiplier. The first two colors give the significant digits, and the third color tells you the power of ten to multiply by.

Here, red is 2 and yellow is 4, giving 24. The orange band is the multiplier, which means 10^3. So 24 × 10^3 = 24,000 ohms (24 kilo-ohms).

As for the other numbers, they would require a different multiplier: 10^2 would give 2,400 ohms, 10^4 would give 240,000 ohms, and 10^5 would give 2,400,000 ohms.