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level: Power

Questions and Answers List

level questions: Power

Question	Answer
The rate at which energy is transferred or the rate at which work is done. Measured in watts (W).	Power
What does the power of an electrical appliance indicate?	How much energy it transfers per second.
The process of moving energy from one place to another or converting it from one form to another.	Energy Transfer
How is power related to energy transfer?	Power is the energy transferred per second.
P = E / t, where P is power, E is energy, and t is time.	Power Equation
What does the power equation (P = E / t) represent?	The relationship between power, energy, and time.
Watts (W), where 1 watt is equal to 1 joule per second.	Unit of Power
What is the unit of power?	Watts (W).
The process of an appliance transferring energy from one store to another.	Energy Transfer in Appliances
How does an appliance's energy transfer relate to its power?	The power shows how much energy it transfers each second.
Determining power using the formula P = E / t.	Calculation of Power
How do you calculate the power of an appliance using the formula P = E / t?	Divide the energy transferred by the time taken.
If a kettle transfers 5000 J of energy in 10 seconds, what is its power?	P = E/t = (5000)/(10) = 500 W
The longer an appliance is used, the more energy it transfers, affecting its power.	Relationship Between Energy Transfer and Power
How does the duration of appliance use impact its energy transfer and power?	The longer it's used, the more energy transferred and the higher the power.
The rate at which electrical devices transfer energy, depending on the potential difference and current.	Power Transfer in Electrical Devices
What factors determine the power transferred by an electrical device?	The potential difference across it and the current through it.
The greater the current through an electrical device, the greater the power transferred.	Influence of Current on Power
How does current affect the power transferred by an electrical device?	The bigger the current, the greater the power transferred.
The greater the potential difference across an electrical device, the greater the power transferred.	Influence of Potential Difference on Power
How does potential difference affect the power transferred by an electrical device?	The bigger the potential difference, the greater the power transferred.
P = IV, where P is power, I is current, and V is potential difference.	Power Transfer in Electrical Devices Equation
What is the formula for calculating power transfer in electrical devices?	P = IV.
If a motor uses a 12 V battery and carries a current of 5 A, what is the power transferred?	P = IV = (5)(12) = 60 W
The relationship expressed by V = IR, which can be used to calculate power.	Voltage-Current-Resistance Relationship
How is the equation V = IR related to calculating power?	It can be rearranged to P = I²R
If a lamp has a resistance of 2 Ω and a current of 5 A, what is the power transferred?	P = I²R = (5)²(2) = 50 W