To find the resistance of the electric iron rated at 1000W and 230V, we can use Ohm's Law and the power formula. Let's break this down step-by-step. ### Step 1: Understand the relationship between power, voltage, and resistance The power (P) consumed by an electrical device can be expressed in terms of voltage (V) and resistance (R) using the formula: \[ P = \frac{V^2}{R} \] Where: - \( P \) is the power in watts (W) - \( V \) is the voltage in volts (V) - \( R \) is the resistance in ohms (Ω) ### Step 2: Rearranging the formula to find resistance We need to find the resistance \( R \). Rearranging the formula gives us: \[ R = \frac{V^2}{P} \] ### Step 3: Plugging in the values Now, we can substitute the given values into the formula. The electric iron has a power rating of 1000W and operates at a voltage of 230V. \[ R = \frac{(230V)^2}{1000W} \] Calculating \( (230V)^2 \): \[ (230)^2 = 52900 \] Now substituting this back into the equation for resistance: \[ R = \frac{52900}{1000} = 52.9Ω \] ### Conclusion: The correct answer Thus, the resistance of the electric iron is **52.9Ω**, which corresponds to option **B**. ### Step 4: Explanation of other options Now, let's analyze the other options to understand why they are incorrect: - **Option A: 51.9Ω** - This value is lower than the calculated resistance. It may arise from a miscalculation or misunderstanding of the power formula. - **Option C: 55.9Ω** - This value is higher than the calculated resistance. It could be a result of incorrectly applying the formula or miscalculating the square of the voltage. - **Option D: 57.6Ω** - This value is significantly higher than the calculated resistance. Similar to option C, it likely results from a miscalculation. ### Common Pitfalls 1. **Misapplying the formula**: Ensure you are using the correct formula for power and rearranging it properly. 2. **Calculating the square of the voltage**: Double-check your arithmetic when squaring the voltage. 3. **Units**: Always keep track of your units (watts, volts, ohms) to avoid confusion. ### Revision Summary - Use the formula \( P = \frac{V^2}{R} \) to relate power, voltage, and resistance. - Rearrange to find resistance: \( R = \frac{V^2}{P} \). - Substitute the given values carefully to avoid calculation errors. - The resistance of the electric iron is **52.9Ω** (Option B).