Question 50

The Correct Answer is D ### 1. Why Option D ("470,000 ohms + or - 10%") is Correct The value of a four-band carbon resistor is determined by the standard color code: * **Band 1 (Yellow):** First significant digit = 4 * **Band 2 (Violet):** Second significant digit = 7 * **Band 3 (Yellow):** Multiplier (10,000 or $10^4$) * **Band 4 (Silver):** Tolerance = $\pm 10\%$ **Calculation:** Value = (Digit 1) (Digit 2) $\times$ Multiplier Value = 47 $\times$ 10,000 Value = **470,000 ohms** **Tolerance:** Silver corresponds to **$\pm 10\%$**. Therefore, the complete value is 470,000 ohms $\pm 10\%$. --- ### 2. Why the Other Options Are Incorrect **A) 74 ohms + or - 5%** * **Value Error:** 74 ohms would require the digits to be Violet (7) and Yellow (4). The actual digits are Yellow (4) and Violet (7). Also, the multiplier (Yellow, $10^4$) is ignored. * **Tolerance Error:** 5% tolerance requires a Gold band, not Silver. **B) 4,700 ohms + or - 10%** * **Value Error:** 4,700 ohms (47 x 100) requires a **Red** multiplier ($10^2$). The actual multiplier band is Yellow ($10^4$). **C) 74,000 ohms + or - 5%** * **Value Error:** This value uses incorrect significant digits (7 and 4 instead of 4 and 7). * **Tolerance Error:** 5% tolerance requires a Gold band, not Silver.