Physics P1 3.2 Electrical power. 0.0 / 5 ? PhysicsEnergyGCSEAQA Created by: Atlanta and JacobCreated on: 04-06-16 18:39 What the power of an appliance? The power of an appliance is rate of transfer of energy per second. 1 of 12 What is the equation to work out power? P = E (over/divided by) t. 2 of 12 What does the P stand for in the equation for power? P is the power in watts (W). 3 of 12 What does the E stand for in the equation for power? E is the energy in joules (J). 4 of 12 What does the t stand for in the equation for power? t is the time taken (in seconds) for energy to be transferred. 5 of 12 What is the equation for efficiency? Efficiency = useful power out (over/divided by) total power in (x100). 6 of 12 What is the unit that power is measured in? Watt (W). 7 of 12 How many joules of electrical energy is transferred to other forms of energy in one second by 1 watt of power? 1 joule. 8 of 12 Wh is power usually given in kilowatts (kW)? Often a watt is too small a unit to be useful, 1 kilowatt = 1000 watts. 9 of 12 How many watts are equivalent to 12 kilowatts? 12000W. 10 of 12 An electric motor transfers 49kJ of electrical energy into kinetic energy in 2 minutes. What is the useful power output of the motor? 400W 11 of 12 **BE SURE THAT YOU PRACTICE EFFICIENCY CALCULATIONS USING BOTH FRACTIONS AND PERCENTAGES** ** 12 of 12
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