If a resistor that is color coded yellow-violet-red is placed across a 25 V source voltage, what value resistor and wattage rating could be used?

Question

If a resistor that is color coded yellow-violet-red is placed across a  25 V source voltage, what value resistor and wattage rating could be used?

Quizplus · Accepted Answer

The color code yellow-violet-red corresponds to the digits 4-7-0, which means the resistor has a value of 4700 ohms. 
To calculate the wattage rating, we need to use Ohm's law which states that Power = Voltage² / Resistance. 
So, Power = (25 V)² / 4700 Ω = 1.32 W, which is greater than 1/4 W but less than 1/2 W. 
Therefore, the closest wattage rating available would be 1/4 W, so the answer is D.

If a Resistor That Is Color Coded Yellow-Violet-Red Is Placed 4700Ω,1/8W4700 \Omega , 1 / 8 W4700Ω,1/8W

If a Resistor That Is Color Coded Yellow-Violet-Red Is Placed $4700 \Omega , 1 / 8 W$