Textbook Question
Consider the circuit of Fig. E25.30. At what rate is electrical energy being converted to other forms in the 8.0 V battery?
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Ch 25: Current, Resistance, and EMF
Young & Freedman Calc14th EditionUniversity PhysicsISBN: 9780321973610
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Table of contents
- Ch 01: Units, Physical Quantities & Vectors41
- Ch 02: Motion Along a Straight Line67
- Ch 03: Motion in Two or Three Dimensions47
- Ch 04: Newton's Laws of Motion23
- Ch 05: Applying Newton's Laws59
- Ch 06: Work & Kinetic Energy14
- Ch 07: Potential Energy & Conservation8
- Ch 08: Momentum, Impulse, and Collisions18
- Ch 09: Rotation of Rigid Bodies42
- Ch 10: Dynamics of Rotational Motion48
- Ch 11: Equilibrium & Elasticity27
- Ch 12: Fluid Mechanics31
- Ch 13: Gravitation35
- Ch 14: Periodic Motion32
- Ch 15: Mechanical Waves25
- Ch 16: Sound & Hearing32
- Ch 17: Temperature and Heat36
- Ch 18: Thermal Properties of Matter38
- Ch 19: The First Law of Thermodynamics33
- Ch 20: The Second Law of Thermodynamics22
- Ch 21: Electric Charge and Electric Field36
- Ch 22: Gauss' Law24
- Ch 23: Electric Potential31
- Ch 24: Capacitance and Dielectrics18
- Ch 25: Current, Resistance, and EMF26
- Ch 26: Direct-Current Circuits30
- Ch 27: Magnetic Field and Magnetic Forces18
- Ch 28: Sources of Magnetic Field10
- Ch 29: Electromagnetic Induction28
- Ch 30: Inductance17
- Ch 31: Alternating Current21
- Ch 32: Electromagnetic Waves1
- Ch 33: The Nature and Propagation of Light20
- Ch 34: Geometric Optics34
- Ch 36: Diffraction25
- Ch 37: Special Relativity20
Young & Freedman Calc14th EditionUniversity PhysicsISBN: 9780321973610Not the one you use?Change textbook
Chapter 25, Problem 41b
A 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. How much energy is transferred?
Verified step by step guidance1
To find the energy transferred, we need to use the formula for electrical energy: \( E = V \times I \times t \), where \( E \) is the energy in joules, \( V \) is the voltage in volts, \( I \) is the current in amperes, and \( t \) is the time in seconds.
First, ensure all units are consistent. The time given is 3.0 ms, which needs to be converted to seconds. Since 1 ms = 0.001 seconds, 3.0 ms = 0.003 seconds.
Substitute the given values into the formula: \( V = 25 \) volts, \( I = 12 \) amperes, and \( t = 0.003 \) seconds.
Calculate the product \( V \times I \times t \) to find the energy transferred.
The result will give you the energy transferred in joules, which is the amount of energy delivered by the defibrillator during the 3.0 ms pulse.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Electric Current
Electric current is the flow of electric charge through a conductor, measured in amperes (A). In the context of a defibrillator, a large current of 12 A is used to stimulate the heart muscle, helping it to resume its normal rhythm. Understanding current is crucial for calculating the energy transferred during the defibrillation process.
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Intro to Current
Voltage
Voltage, measured in volts (V), is the potential difference that drives the flow of electric current through a circuit. In a defibrillator, a voltage of 25 V is applied to the body to create the necessary conditions for current flow. Voltage is essential for determining the power and energy involved in the defibrillation process.
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Energy Transfer
Energy transfer in electrical systems is calculated using the formula: Energy = Power × Time, where Power = Voltage × Current. For the defibrillator, the energy transferred can be found by multiplying the power (25 V × 12 A) by the duration of the current flow (3.0 ms). This concept is key to understanding how much energy is delivered to the heart during defibrillation.
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Related Practice
Textbook Question
Consider the circuit of Fig. E25.30 Show that the power output of the 16.0 V battery equals the overall rate of consumption of electrical energy in the rest of the circuit.
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Textbook Question
Electric eels generate electric pulses along their skin that can be used to stun an enemy when they come into contact with it. Tests have shown that these pulses can be up to 500 V and produce currents of 80 mA (or even larger). A typical pulse lasts for 10 ms. What power and how much energy are delivered to the unfortunate enemy with a single pulse, assuming a steady current?
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Textbook Question
The battery for a certain cell phone is rated at 3.70 V. According to the manufacturer, it can produce 3.15 × 104 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.
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Textbook Question
A typical small flashlight contains two batteries, each having an emf of 1.5 V, connected in series with a bulb having resistance 17 Ω. If the internal resistance of the batteries is negligible, what power is delivered to the bulb?
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Textbook Question
A typical small flashlight contains two batteries, each having an emf of 1.5 V, connected in series with a bulb having resistance 17 Ω. If the batteries last for 5.0 h, what is the total energy delivered to the bulb?
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