If you have a voltage of 120 volts entering your house and a light bulb with 0.625 amperes flowing through it, how many watts is your light bulb?
A. 25 watts
B. 50 watts
C. 150 watts
D. 75 watts
Answer (2)
The problem provides voltage and current.
Use the formula P = V × I to calculate power.
Substitute V = 120 volts and I = 0.625 amperes into the formula.
Calculate the power: 75 watts .
Explanation
Problem Analysis We are given the voltage and current of a light bulb and asked to find the power in watts.
Relevant Formula The formula that relates power (P), voltage (V), and current (I) is: P = V I
Substitution We are given that the voltage V = 120 volts and the current I = 0.625 amperes. Substituting these values into the formula, we get: P = 120 volts × 0.625 amperes
Calculation Calculating the power: P = 75 watts
Final Answer Therefore, the power of the light bulb is 75 watts.
Examples
Understanding the relationship between voltage, current, and power is crucial in electrical engineering and everyday life. For example, when choosing appliances, it's important to know their power consumption to avoid overloading circuits. If you have a device that runs on 12 volts and draws 2 amperes, its power consumption is 24 watts. Knowing this helps you select the right power supply and manage energy usage effectively.
The power consumed by the light bulb is 75 watts, calculated using the formula P = V × I with 120 volts and 0.625 amperes. Therefore, the correct answer is option D. 75 watts.
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