Energy and Power Questions

• If you used 600 W of power for 60 h, you have used
• If you used 400 W of power for 30 h, you have used
• A 220 Ω resistor dissipates 3 W. The voltage is
• A power supply produces a 0.6 W output with an input of 0.7 W. Its percentage of efficiency is
• A 75 Ω load uses 2 W of power. The output voltage of the power supply is approximately
• In 0.025 W, there are
• How many watt-hours represent 65 W used for 18 h?
• A 15 V source is connected across a 12 Ω resistor. How much energy is used in three minutes?
• A 120 Ω resistor must carry a maximum current of 25 mA. Its rating should be at least
• A 68 Ω resistor is connected across the terminals of a 3 V battery. The power dissipation of the resistor is
• A 3.3 kΩ resistor dissipates 0.25 W. The current is
• A given power supply is capable of providing 6 A for 3.5 h. Its ampere-hour rating is
• At the end of a 14 day period, your utility bill shows that you have used 18 kWh. What is your average daily power?
• Three hundred joules of energy are consumed in 15 s. The power is
• For 12 V and 40 mA, the power is
• When the pointer of an analog ohmmeter reads close to zero, the resistor being measured is
• If it takes 400 ms to use 12,000 J of energy, the power is
• A 33 Ω half-watt resistor and a 330 Ω half-watt resistor are connected across a 12 V source. Which one(s) will overheat?
• The power rating of a carbon-composition resistor that is to handle up to 1.2 W should be
• When the current through a 12 kΩ resistor is 8 mA, the power is