A piece of electronics requires 80 W of power when connected to a 120 V outlet. How much energy is ised in 6 hrs. How many amps of curtrent does it draw. what is the resistance
The correct answer and explanation is:
To solve this, we will use three basic formulas from electricity:
- Energy (E) = Power (P) × Time (t)
- Current (I) = Power (P) ÷ Voltage (V)
- Resistance (R) = Voltage (V) ÷ Current (I) or using Ohm’s Law: R = V² ÷ P
Given:
- Power = 80 watts
- Voltage = 120 volts
- Time = 6 hours
Step 1: Calculate Energy Used in 6 Hours
First, convert time to seconds (if energy is in joules) or leave it in hours for kilowatt-hours.
Energy in kilowatt-hours (kWh): Energy=80 W1000×6 h=0.08×6=0.48 kWh\text{Energy} = \frac{80 \text{ W}}{1000} \times 6 \text{ h} = 0.08 \times 6 = 0.48 \text{ kWh}
Energy in joules: Energy=80 W×6×3600 s=80×21600=1,728,000 J\text{Energy} = 80 \text{ W} \times 6 \times 3600 \text{ s} = 80 \times 21600 = 1,728,000 \text{ J}
Step 2: Calculate Current Drawn
I=PV=80120=0.6667 A≈0.67 amperesI = \frac{P}{V} = \frac{80}{120} = 0.6667 \text{ A} \approx 0.67 \text{ amperes}
Step 3: Calculate Resistance
R=V2P=120280=1440080=180 ohmsR = \frac{V^2}{P} = \frac{120^2}{80} = \frac{14400}{80} = 180 \text{ ohms}
Final Answers:
- Energy Used: 0.48 kWh or 1,728,000 joules
- Current Drawn: 0.67 amperes
- Resistance: 180 ohms
Explanation (Approx. 300 Words):
Electric power is the rate at which energy is used. It is calculated by multiplying the voltage and the current. In this question, the electronic device uses 80 watts of power when plugged into a 120-volt outlet. The energy consumed depends on how long the device is operating. Since the time given is 6 hours, the total energy used is the power multiplied by time. To express this in kilowatt-hours, which is a standard unit used by electric companies, the power in watts is divided by 1000 and then multiplied by time in hours. This gives 0.48 kWh. If you want to know the energy in joules, multiply power in watts by time in seconds. Six hours equals 21,600 seconds, and 80 watts times that gives 1,728,000 joules.
To find the current the device draws, divide the power by the voltage. Since the device uses 80 watts and the voltage supply is 120 volts, the current is about 0.67 amperes. This tells us how many charges flow through the circuit per second. Finally, to find the resistance of the device, you can use the formula that involves voltage squared divided by power. This gives 180 ohms. Resistance tells us how much the device resists the flow of electric current. These values help understand how the device behaves electrically and are useful in checking compatibility with power sources and ensuring safe operation.