Math Problem Statement

A typical American family uses 860 kWh of electricity a month. What is the average current in the 100 V power line to the house?

Solution

To find the average current in the power line, we can use the formula for electrical power:

P=VIP = VI

Where:

  • PP is the power (in watts, W),
  • VV is the voltage (in volts, V),
  • II is the current (in amperes, A).

However, the energy consumption is given in kilowatt-hours (kWh), not watts. So, we first convert the energy usage to total power over time and then calculate the average current.

Step 1: Convert kWh to Watts

The family uses 860 kWh per month. We convert that to watts by recalling that:

1 kWh=1000 W×1 hour1 \text{ kWh} = 1000 \text{ W} \times 1 \text{ hour}

So, the total energy consumption is:

860 kWh=860×1000 Wh=860,000 Wh860 \text{ kWh} = 860 \times 1000 \text{ Wh} = 860,000 \text{ Wh}

Step 2: Determine the Average Power Consumption

Since 1 month has approximately 30 days, and each day has 24 hours, the total time is:

T=30×24=720 hoursT = 30 \times 24 = 720 \text{ hours}

Now, the average power consumption PP is the total energy divided by the time:

P=860,000 Wh720 hours=1194.44 WP = \frac{860,000 \text{ Wh}}{720 \text{ hours}} = 1194.44 \text{ W}

Step 3: Calculate the Average Current

Now, using the power equation P=VIP = VI, we can solve for the current II:

I=PV=1194.44 W100 V=11.94 AI = \frac{P}{V} = \frac{1194.44 \text{ W}}{100 \text{ V}} = 11.94 \text{ A}

Thus, the average current in the power line is approximately:

I=11.94 AI = 11.94 \text{ A}

Conclusion:

The average current flowing through the 100 V power line to the house is 11.94 A.


Would you like further details or have any questions? Here are five related questions to expand on this topic:

  1. How would the current change if the voltage were increased to 120 V?
  2. How is electrical energy measured and billed in a household?
  3. What factors can affect the power consumption of a household?
  4. What is the difference between alternating current (AC) and direct current (DC)?
  5. How do you convert electrical power from watts to kilowatts?

Tip: Keeping energy-efficient appliances can significantly reduce your monthly kWh consumption.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Electricity
Power
Current
Energy

Formulas

P = VI (Power = Voltage × Current)
Energy (in kWh) = Power (in watts) × Time (in hours)

Theorems

-

Suitable Grade Level

Grades 9-12