$CATEGORY: Science - Khan Academy/12.Electricity/12.Electricity--Electric Power

//Multiple Choice

The SI unit of electric power is\: {
    =Watt
    ~Joule
    ~Ampere
    ~Ohm
}

Electric power is given by which of the following formulas? {
    ~P\=VI
    ~P\=I²R
    ~P\=V²/R
    =All of the above
}

Which of the following is the correct expression for electrical energy? {
    ~E\=P×t
    ~E\=VI×t
    ~E\=I²Rt
    =All of the above
}

Which device is used to measure electrical energy consumed? {
    ~Ammeter
    ~Voltmeter
    =Energy meter
    ~Galvanometer
}

The power of a device is 200 W. It operates for 2 hours. How much energy is consumed in kilowatt-hour? {
    =0.4 kWh
    ~2 kWh
    ~1 kWh
    ~0.2 kWh
}

Electric power in terms of voltage and resistance is given by {
    =P\=V²/R
    ~P\=V²R
    ~P\=IR/V
    ~P\=I/V
}

//True or False

Electric power is the rate at which electric energy is consumed. {T}

The SI unit of electrical energy is kilowatt-hour. {F} (Joule is the SI unit, kWh is a practical unit)

A 60 W bulb consumes more power than a 100 W bulb. {F}

The electrical energy consumed by an appliance depends on its power rating and the time for which it is used. {T}

The power delivered by a source is inversely proportional to the resistance of the circuit if the voltage is constant. {T}

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