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P7: Quiz 11
P7: Quiz 11
1) charge, work, resistance
A moving charge is able to transfer energy because the CHARGE does WORK against the RESISTANCE in a circuit
2) A battery-powered electric fan transfers energy electrically from the chemical energy stores of the battery in the fan to the kinetic energy stores of the motor and blades in the fan (useful energy transfer). Some of the energy is also transferred to the thermal energy stores of the motor, fan and the surroundings; this energy is wasted.
3) A washing machine transfers energy electrically from the mains ac supply to the thermal energy stores of the water (the water become hot) and the kinetic energy stores of the motor and drum (the washing machine drum spins).
4)
a) Power is a rate of energy transfer (or the rate of energy transfer per second)
b) 1 watt is 1 joule of energy transferred per second
c) energy transfer = power x time, or E = Pt
Energy transfer is in joules (J), power is in watts (W) and time is in seconds (s)
A moving charge is able to transfer energy because the CHARGE does WORK against the RESISTANCE in a circuit
2) A battery-powered electric fan transfers energy electrically from the chemical energy stores of the battery in the fan to the kinetic energy stores of the motor and blades in the fan (useful energy transfer). Some of the energy is also transferred to the thermal energy stores of the motor, fan and the surroundings; this energy is wasted.
3) A washing machine transfers energy electrically from the mains ac supply to the thermal energy stores of the water (the water become hot) and the kinetic energy stores of the motor and drum (the washing machine drum spins).
4)
a) Power is a rate of energy transfer (or the rate of energy transfer per second)
b) 1 watt is 1 joule of energy transferred per second
c) energy transfer = power x time, or E = Pt
Energy transfer is in joules (J), power is in watts (W) and time is in seconds (s)
5) 1,200 J
6) 108 kJ
7)
a) 5,400 seconds
b) 3 W
8) 17 minutes
9)
a) 3,600,000 J (or 1,600 KJ)
b) 2,932,500 J (or 2,932.5 KJ)
c) 667,500 J (or 667.5 KJ)
5) 1,200 J
6) 108 kJ
7)
a) 5,400 seconds
b) 3 W
8) 17 minutes
9)
a) 3,600,000 J (or 1,600 KJ)
b) 2,932,500 J (or 2,932.5 KJ)
c) 667,500 J (or 667.5 KJ)
Questions
1) Fill in the gaps below.
A moving charge is able to transfer energy because the ______ does ______against the ______in a circuit
2) Discuss the energy transfers for a battery powered electric fan. Include the energy transfers to useful and wasted energy stores.
3) Discuss the energy transfers for a washing machine that is plugged into the mains electricity supply. Include the energy transfers to useful and wasted energy stores.
4)
a) What is power?
b) Power is measured in watts; what is 1 watt is other units?
c) Write the equation that links power, energy transfer and time. Give the units for each of the variables and write down the formula triangle.
5) A 4 W battery powered fan is on for 5 minutes. Calculate the energy transferred whilst the fan is on.
6) A 600 W hair dryer is on for 3 minutes. Calculate the energy transferred whilst the hair dryer is on. Give your answer in kilojoules (kJ).
7) A phone charger transfers 16,200 joules of energy when it charges a phone for 1.5 hours.
a) How long is the phone charger on for in seconds?
b) Calculate the power of the phone charger.
8) An 890 W oven transfers 907,800 joules of energy to cook a frozen pizza. Calculate how long the oven is on for. Give your answer in minutes.
9) A washing machine has two different modes; normal and eco. Some details about these modes are shown below.
1) Fill in the gaps below.
A moving charge is able to transfer energy because the ______ does ______against the ______in a circuit
2) Discuss the energy transfers for a battery powered electric fan. Include the energy transfers to useful and wasted energy stores.
3) Discuss the energy transfers for a washing machine that is plugged into the mains electricity supply. Include the energy transfers to useful and wasted energy stores.
4)
a) What is power?
b) Power is measured in watts; what is 1 watt is other units?
c) Write the equation that links power, energy transfer and time. Give the units for each of the variables and write down the formula triangle.
5) A 4 W battery powered fan is on for 5 minutes. Calculate the energy transferred whilst the fan is on.
6) A 600 W hair dryer is on for 3 minutes. Calculate the energy transferred whilst the hair dryer is on. Give your answer in kilojoules (kJ).
7) A phone charger transfers 16,200 joules of energy when it charges a phone for 1.5 hours.
a) How long is the phone charger on for in seconds?
b) Calculate the power of the phone charger.
8) An 890 W oven transfers 907,800 joules of energy to cook a frozen pizza. Calculate how long the oven is on for. Give your answer in minutes.
9) A washing machine has two different modes; normal and eco. Some details about these modes are shown below.
a) Work out the energy transferred when the washing machine is on normal mode.
b) Work out the energy transferred when the washing machine is on eco mode.
c) Calculate the energy saving when the washing machine is on eco mode.
b) Work out the energy transferred when the washing machine is on eco mode.
c) Calculate the energy saving when the washing machine is on eco mode.