# Which Light Bulb Has a Larger Resistance?

## Question:

A 60W light bulb and a 100W light bulb are each rated at 120V. Which light bulb has a larger resistance?

## Final Answer:

The 100W light bulb has a larger resistance than the 60W bulb.

To determine which light bulb has a larger resistance, we need to understand the relationship between power, voltage, and resistance in a light bulb. The resistance of a light bulb can be calculated using the formula P = V²/R, where P is the power in watts, V is the voltage in volts, and R is the resistance in ohms.

Since both the 60W and 100W light bulbs have the same voltage rating of 120V, we can compare their resistances by rearranging the formula as R = V²/P. Plugging in the values, we get R = 120²/60 for the 60W bulb and R = 120²/100 for the 100W bulb.

After performing the calculations, we find that the resistance of the 60W bulb is 240 ohms, while the resistance of the 100W bulb is 144 ohms. Therefore, the 100W light bulb has a larger resistance compared to the 60W bulb.

**Additional Information:**

The default resistance of a real bulb is typically about 58 ohms, similar to the small flashlight bulbs commonly used in classroom experiments. Applying more than 6 volts across a real bulb can cause it to burn out, making it unusable. This corresponds to a current of approximately 102.5 mA.