Question

An incandescent light bulb is rated at a power of 60 W when connected to a 120-V source. What current passes through the light bulb when it is connected to a 120-V source? What current would pass through the light bulb when it is connected to a 250-V source?

Answer 1

The current passing through the light bulb when connected to a 120-V source is 0.5 A. When connected to a 250-V source, the current is 0.24 A.

Step-by-step explanation:

To find the current passing through the light bulb, we can use Ohm's Law, which states that current (I) is equal to voltage (V) divided by resistance (R). In this case, the voltage is given as 120 V, and the power rating of the light bulb is given as 60 W. Since power (P) is equal to voltage multiplied by current, we can rearrange the equation to solve for current. First, we need to find the resistance of the light bulb by using the formula P = V^2 / R. Rearranging the equation, we have R = V^2 / P. Plugging in the values, we get R = (120 V)^2 / 60 W = 240 Ohms. Now we can use Ohm's Law to find the current. I = V / R = 120 V / 240 Ohms = 0.5 A.

When the same light bulb is connected to a 250-V source, we can use the same equation to find the current. First, we need to find the resistance using the formula R = V^2 / P. Plugging in the values, we get R = (250 V)^2 / 60 W = 1041.67 Ohms. Now we can use Ohm's Law to find the current. I = V / R = 250 V / 1041.67 Ohms = 0.24 A.