27. Resistors & DC Circuits
Power in Circuits
27. Resistors & DC Circuits
Power in Circuits
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- Multiple Choice
A hair dryer operates at 120 V (the voltage produced by a household outlet), and outputs 1200 W of energy. For this problem, treat the hair dryer as a single resistor.
(a) At what current does the hair dryer operate?
(b) What is the resistance of the hair dryer?2194views22rank1comments - Multiple Choice
An incandescent lightbulb produces 100 W of light. If this lightbulb operates at 25% efficiency (meaning that out of all the power it generates, only 25% is released as light), what resistance must the lightbulb have if it operates at 120 V?
879views30rank7comments - Multiple ChoiceA toaster is connected to a wall outlet, which provides a potential difference of . What is the effective resistance of the toaster?378views
- Multiple ChoiceA certain resistor is connected across a battery and dissipates of power. The battery is replaced with an battery. How much power is dissipated in the resistor now?360views
- Textbook QuestionA typical small flashlight contains two batteries, each having an emf of 1.5 V, connected in series with a bulb having resistance 17 Ω. ((b) If the batteries last for 5.0 h, what is the total energy delivered to the bulb?631views
- Textbook QuestionA typical small flashlight contains two batteries, each having an emf of 1.5 V, connected in series with a bulb having resistance 17 Ω. (a) If the internal resistance of the batteries is negligible, what power is delivered to the bulb?901views
- Textbook QuestionThe battery for a certain cell phone is rated at 3.70 V. According to the manufacturer it can produce 3.15 * 10^4 J of electrical energy, enough for 5.25 h of operation, before needing to be recharged. Find the average current that this cell phone draws when turned on.822views
- Textbook QuestionA heart defibrillator is used to enable the heart to start beating if it has stopped. This is done by passing a large current of 12 A through the body at 25 V for a very short time, usually about 3.0 ms. (b) how much energy is transferred?929views