Textbook Question
A copper transmission cable km long and cm in diameter carries a current of A. How much electrical energy is dissipated as thermal energy every hour?
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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 35: Interference19
- Ch 36: Diffraction25
- Ch 37: Special Relativity20
- Ch 38: Photons: Light Waves Behaving as Particles15
- Ch 39: Particles Behaving as Waves26
- Ch 40: Quantum Mechanics I: Wave Functions21
- Ch 41: Quantum Mechanics II: Atomic Structure25
- Ch 42: Molecules and Condensed Matter18
- Ch 43: Nuclear Physics16
- Ch 44: Particle Physics and Cosmology23
Young & Freedman Calc14th EditionUniversity PhysicsISBN: 9780321973610Not the one you use?Change textbook
Chapter 25, Problem 28a
An idealized ammeter is connected to a battery as shown in Fig. E. Find the reading of the ammeter.
Verified step by step guidance1
First, identify the components in the circuit: a battery with a voltage of 12.0 V, a resistor with a resistance of 16.8 Ω, and another resistor with a resistance of 12.0 Ω. The ammeter is connected in series with the 12.0 Ω resistor.
To find the reading of the ammeter, we need to calculate the current flowing through the circuit. Use Ohm's Law, which states that the current (I) is equal to the voltage (V) divided by the total resistance (R) in the circuit: I = V / R.
Calculate the total resistance in the circuit. Since the resistors are in series, the total resistance is the sum of the individual resistances: R_total = 16.8 Ω + 12.0 Ω.
Substitute the values into Ohm's Law: I = 12.0 V / R_total. This will give you the current flowing through the circuit, which is the reading of the ammeter.
Ensure that the units are consistent and check your calculations for any errors. The ammeter reading will be in amperes (A), which is the standard unit for current.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Ohm's Law
Ohm's Law is a fundamental principle in electronics and electrical engineering, stating that the current (I) through a conductor between two points is directly proportional to the voltage (V) across the two points and inversely proportional to the resistance (R) of the conductor. It is mathematically expressed as I = V/R. This law is essential for calculating the current in the circuit shown in the image.
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Series and Parallel Circuits
In a series circuit, components are connected end-to-end, so the same current flows through each component. In a parallel circuit, components are connected across the same voltage source, allowing the current to divide among the paths. The circuit in the image is a series circuit, as the resistors and the ammeter are connected in a single loop, affecting how the total resistance and current are calculated.
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Ideal Ammeter
An ideal ammeter is a device used to measure the current flowing through a circuit. It is assumed to have zero resistance, meaning it does not affect the current it measures. In the given circuit, the ammeter is connected in series with the resistors, and its reading will be the same as the current flowing through the entire circuit, calculated using Ohm's Law.
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Related Practice
Textbook Question
A hollow aluminum cylinder is m long and has an inner radius of cm and an outer radius of cm. Treat each surface (inner, outer, and the two end faces) as an equipotential surface. At room temperature, what will an ohmmeter read if it is connected between (a) the opposite faces and (b) the inner and outer surfaces?
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Textbook Question
The circuit shown in Fig. E contains two batteries, each with an emf and an internal resistance, and two resistors. Find the potential difference of point with respect to point .
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Textbook Question
An idealized ammeter is connected to a battery as shown in Fig. E. Find the terminal voltage of the battery.
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Textbook Question
An idealized ammeter is connected to a battery as shown in Fig. E. Find the current through the - resistor.
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Textbook Question
What is the resistance of a carbon rod at °C if its resistance is at °C?
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