🔍 Key Concepts

• Power formula relationship between voltage (E), current (I), resistance (R), and power (P) • Using Ohm's Law to relate voltage, current, and resistance • How to combine formulas to express power in terms of voltage and resistance

💭 Think About

• Start from a basic power formula (for example, P = E × I or P = I² × R) and think about which one lets you bring voltage and resistance together. • Use Ohm’s Law (E = I × R) to substitute into the power formula so that you end up with an equation that has only voltage (E), resistance (R), and power (P). • Once you have a formula for voltage in terms of power and resistance, plug in 20 watts and 2000 ohms and solve for the maximum voltage.

✅ Before You Answer

• Make sure units are consistent: watts for power, ohms for resistance, volts for voltage. • Double-check your algebra when you rearrange the power formula to solve for voltage. • After you calculate the voltage, verify that plugging it back into the power formula gives approximately 20 watts.