Electricity and Power Flashcard

Front

What is the formula to calculate power in an electrical circuit?

Back

W = V × A, where W is power in watts, V is voltage in volts, and A is current in amperes.

Front

How much does it cost to operate an electric device?

Back

Cost = (Power in kilowatts) × (Time in hours) × (Cost per kilowatt-hour).

Front

What is the watt rating of an electric device that uses 10 amperes in a 120-volt circuit?

Back

W = 120 volts × 10 amperes = 1200 watts.

Front

If a device operates for 1 hour at 1200 watts, how many kilowatt-hours does it consume?

Back

1.2 kilowatt-hours (since 1200 watts = 1.2 kilowatts).

Front

What is the cost of running a 1200-watt device for 1 hour at a rate of $0.10 per kilowatt-hour?

Back

$0.12 (1.2 kWh × $0.10/kWh).

Front

What is a 'hot wire' in electrical terms?

Back

A hot wire is a current-carrying conductor under electrical pressure.

Front

How do you convert amperes to kilowatts?

Back

Use the formula: Kilowatts = (Voltage × Amperes) / 1000.

Front

What is the watt rating of a device that uses 30 amps in a 120-volt circuit?

Back

W = 120 volts × 30 amps = 3600 watts.

Front

If a device requires 7.5 amperes in a 120-volt circuit, how many kilowatts does it use?

Back

0.9 kilowatts (W = 120 × 7.5 = 900 watts, then 900/1000 = 0.9 kW).

Front

What is the cost to operate a device that uses 7.5 amperes for 2 hours at $0.15 per kilowatt-hour?

Back

$1.75 (W = 120 × 7.5 = 900 watts; 900 watts = 0.9 kW; Cost = 0.9 kW × 2 hours × $0.15/kWh).