Power quiz #1 Flashcards
Power quiz #1
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To what is a watt equivalent in terms of SI units?
A watt is equivalent to one joule per second (1 W = 1 J/s). What physical quantity does a watt measure?
A watt measures power, which is the rate at which work is done or energy is transferred. How many joules of energy does a 100-watt light bulb use in one hour?
A 100-watt light bulb uses 360,000 joules of energy in one hour, calculated as E = P × t = 100 W × 3600 s. How do you calculate the energy used by a 100-watt light bulb in one hour?
Multiply the power (100 W) by the time in seconds (3600 s) to get 360,000 joules. What is a watt equal to in terms of energy and time?
A watt is equal to one joule of energy transferred per second. What is one watt equal to in SI base units?
One watt is equal to one joule per second (1 W = 1 J/s). Which symbol is commonly used to represent power?
The symbol 'P' is commonly used to represent power. In which unit is power measured?
Power is measured in watts (W). What are the SI units for power?
The SI unit for power is the watt (W), which is equivalent to joules per second (J/s). If you do 90 joules of work in 30 seconds, how much power have you generated?
Power = Work / Time = 90 J / 30 s = 3 W. What is the SI unit of power?
The SI unit of power is the watt (W). What are the units of power in the International System?
The units of power in the International System are watts (W), or joules per second (J/s). In an electric circuit, by which component is true power dissipated?
True power is dissipated by the resistive elements of a circuit. How are power ratings used to describe machines?
Power ratings indicate how quickly a machine can do work or transfer energy. How do you calculate the power of a single laser pulse if you know the energy and duration?
Power is calculated as the energy of the pulse divided by its duration: P = E / t. How do you calculate the power dissipated by a resistor if you know the energy transferred per second?
Power dissipated by a resistor is equal to the energy transferred per second, P = E / t. How do you determine the power dissipated by a resistor if you know the voltage across and current through it?
Power dissipated by a resistor can be calculated as P = V × I, where V is voltage and I is current. How do you calculate the average power output of a weightlifter lifting a mass to a certain height in a given time?
Average power output is calculated as P = (m × g × h) / t, where m is mass, g is acceleration due to gravity, h is height, and t is time. How do you determine the power dissipated by a light bulb when the circuit is open?
When the circuit is open, no current flows, so the power dissipated by the bulb is zero. If four students run up the same stairs in different times, which student has the largest power output?
The student who completes the work in the shortest time has the largest power output. Which unit is equivalent to a watt?
A watt is equivalent to one joule per second (1 W = 1 J/s). How do you calculate the power dissipated by a resistor if you know the current and resistance?
Power can be calculated as P = I^2 × R, where I is current and R is resistance. Which of the following is not a unit of power: watt, joule, or joule per second?
Joule is not a unit of power; it is a unit of energy. What does the power rating on a light bulb describe?
The power rating on a light bulb describes the rate at which it uses energy. What is the unit for power in the SI system?
The unit for power in the SI system is the watt (W). What is the difference between energy and power?
Energy is the capacity to do work, measured in joules, while power is the rate at which energy is transferred or work is done, measured in watts. Which term describes the rate at which work is done?
Power describes the rate at which work is done. How do you calculate the heat output of an electric furnace rated at 15 kilowatts?
The heat output is 15,000 joules per second (15 kW = 15,000 W), so in t seconds, the total heat output is Q = 15,000 × t joules. How is average power defined?
Average power is defined as the total work done or energy transferred divided by the total time taken: P = W / t. How is electrical power commonly measured?
Electrical power is commonly measured in watts (W). How do you calculate the heat energy produced by a 1500-watt heater operating for 2 hours?
Heat energy produced is E = P × t = 1500 W × 7200 s = 10,800,000 joules. What is power in the context of physics?
Power is the rate at which work is done or energy is transferred. How much heat energy does a 1500-watt heater produce in 2 hours?
A 1500-watt heater produces 10,800,000 joules of heat energy in 2 hours. How do you calculate the power produced by a light bulb with a voltage of 120 volts and a current of 0.045 amps?
Power is calculated as P = V × I = 120 V × 0.045 A = 5.4 W. How do you determine which scenario uses the most power?
The scenario with the highest rate of energy transfer or work done per unit time uses the most power. If a light draws 220 watts on a 120 volt circuit, what is the current?
Current is I = P / V = 220 W / 120 V ≈ 1.83 A. If you move an 8-newton weight five meters in 4 seconds, how much power have you generated?
Work done = 8 N × 5 m = 40 J; Power = 40 J / 4 s = 10 W. What is the general formula for power in terms of work and time?
Power is given by P = W / t, where W is work and t is time. If a device uses 280 watts of power continuously for a day, how much energy does it consume?
Energy consumed = Power × Time = 280 W × 86,400 s = 24,192,000 joules. An electric device uses 650 watts of power at 120 volts. What is the current?
Current is I = P / V = 650 W / 120 V ≈ 5.42 A.
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