Power and Energy in Circuits

The video tutorial covers electrical energy transfers, focusing on energy stores and transfers when current flows. It explains how energy is transferred in circuits, using motors as an example. The tutorial introduces equations for calculating energy transferred, such as energy equals charge flow times potential difference. It also covers power equations, including power equals current times potential difference and power equals current squared times resistance, with practical examples. The video concludes with a summary of key equations for calculating energy and power.

What happens when current flows in a circuit?

• Energy is stored.

• Work is done and energy is transferred.

• The circuit breaks.

• The potential difference decreases.

Which factors determine the amount of energy transferred in a circuit?

• Charge flow and potential difference

• Resistance and current

• Voltage and resistance

• Current and time

How do you calculate power using current and potential difference?

• Power = Current + Potential Difference

• Power = Current / Potential Difference

• Power = Current x Potential Difference

• Power = Current - Potential Difference

What is the power of a device that uses 5 amps and 230 volts?

• 1150 watts

• 1.15 watts

• 115 kilowatts

• 1.15 kilowatts

How do you convert watts to kilowatts?

• Multiply by 1000

• Divide by 1000

• Add 1000

• Subtract 1000

Which equation is used to calculate power using current squared and resistance?

• Power = Current Squared x Resistance

• Power = Resistance / Current

• Power = Current + Resistance

• Power = Current x Resistance

What is the reading on an ammeter if a motor with a 60 watt power rating and 9 ohms resistance is used?

• 26 amps

• 0.26 amps

• 6.2 amps

• 2.6 amps

What is the unit of power?

• Volts

• Ohms

• Watts

• Amps

Which equation is NOT used to calculate energy transferred?

• Energy Transferred = Current x Time

• Energy Transferred = Charge Flow x Potential Difference

• Power = Current x Potential Difference

• Power = Current Squared x Resistance

What is the correct formula for calculating energy transferred?

• Energy Transferred = Charge Flow / Potential Difference

• Energy Transferred = Charge Flow x Potential Difference

• Energy Transferred = Charge Flow - Potential Difference

• Energy Transferred = Charge Flow + Potential Difference