교과서 질문
Neon signs require 12 kV for their operation. To operate from a 240-V line, what must be the ratio of secondary to primary turns of the transformer? What would the voltage output be if the transformer were connected in reverse?
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Ch. 29 - Electromagnetic Induction and Faraday's Law
Giancoli Douglas5th editionPhysics for Scientists and EngineersISBN: 9780137488179
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Table of contents
- Ch. 01 - Introduction, Measurement, Estimating10
- Ch. 02 - Describing Motion: Kinematics in One Dimension30
- Ch. 03 - Kinematics in Two or Three Dimensions; Vectors15
- Ch. 04 - Dynamics: Newton's Laws of Motion16
- Ch. 05 - Using Newton's Laws: Friction, Circular Motion, Drag Forces22
- Ch. 06 - Gravitation and Newton's Synthesis10
- Ch. 07 - Work and Energy21
- Ch. 08 - Conservation of Energy33
- Ch. 09 - Linear Momentum26
- Ch. 10 - Rotational Motion41
- Ch. 11 - Angular Momentum; General Rotation27
- Ch. 12 - Static Equilibrium; Elasticity and Fracture27
- Ch. 13 - Fluids28
- Ch. 14 - Oscillations14
- Ch. 15 - Wave Motion35
- Ch. 16 - Sound5
- Ch. 17 - Temperature, Thermal Expansion, and the Ideal Gas Law40
- Ch. 18 - Kinetic Theory of Gases18
- Ch. 19 - Heat and the First Law of Thermodynamics31
- Ch. 20 - Second Law of Thermodynamics32
- Ch. 21 - Electric Charge and Electric Field7
- Ch. 23 - Electric Potential20
- Ch. 24 - Capacitance, Dielectrics, Electric Energy, Storage15
- Ch. 25 - Electric Current and Resistance32
- Ch. 26 - DC Circuits22
- Ch. 27 - Magnetism21
- Ch. 28 - Sources of Magnetic Field24
- Ch. 29 - Electromagnetic Induction and Faraday's Law21
- Ch. 30 - Inductance, Electromagnetic Oscillations, and AC Circuits42
- Ch. 31 - Maxwell's Equations and Electromagnetic Waves25
- Ch. 32 - Light: Reflection and Refraction42
- Ch. 33 - Lenses and Optical Instruments21
- Ch. 34 - The Wave Nature of Light: Interference and Polarization26
- Ch. 35 - Diffraction24
- Ch. 36 - The Special Theory of Relativity29
- Ch. 38 - Quantum Mechanics1
- Ch. 40 - Molecules and Solids6
- Ch. 43 - Elementary Particles3
- Ch. 44 - Astrophysics and Cosmology9
Giancoli Douglas5th editionPhysics for Scientists and EngineersISBN: 9780137488179당신이 사용하는 게 아니라요?교과서 변경
28장, 문제 48
A model-train transformer plugs into 120-V ac and draws 0.35 A while supplying 6.5 A to the train.
(a) What voltage is present across the tracks?
(b) Is the transformer step-up or step-down?
검증된 단계별 안내1
Step 1: Use the principle of conservation of power for an ideal transformer. The input power (primary side) is equal to the output power (secondary side). The formula is: , where (voltage times current).
Step 2: Calculate the output voltage across the tracks using the formula: . Substitute the given values: V, A, and A.
Step 3: Simplify the ratio and multiply it by to find . This will give the voltage across the tracks.
Step 4: Determine whether the transformer is step-up or step-down by comparing the input voltage () to the output voltage (). If , it is a step-down transformer; otherwise, it is step-up.
Step 5: Conclude the solution by stating the calculated output voltage and whether the transformer is step-up or step-down based on the comparison in Step 4.
비슷한 문제에 대한 검증된 영상 답변:
이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
영상 길이:
7m도움이 되었나요?
주요 개념
질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.
Ohm's Law
Ohm's Law states that the current (I) flowing 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. This relationship is expressed as V = I × R. Understanding this law is crucial for analyzing electrical circuits, including transformers, as it helps determine the voltage and current relationships.
추천 영상:
가이드 코스
03:07
Resistance and Ohm's Law
Transformer Basics
A transformer is an electrical device that transfers electrical energy between two or more circuits through electromagnetic induction. It consists of primary and secondary coils, and its operation is based on the principle that a changing current in the primary coil creates a changing magnetic field, inducing a voltage in the secondary coil. The voltage ratio between the primary and secondary coils determines whether the transformer is a step-up or step-down transformer.
추천 영상:
가이드 코스
03:00Transformers
Power Conservation in Transformers
In an ideal transformer, the power input to the primary coil equals the power output from the secondary coil, expressed as P_primary = P_secondary. This means that the product of voltage and current remains constant, allowing for the calculation of unknown voltages or currents. This principle is essential for solving the given problem, as it helps determine the voltage across the tracks based on the current supplied to the train.
추천 영상:
가이드 코스
03:00Transformers
관련 실천
교과서 질문
If 75 MW of power at 45 kV (rms) arrives at a town from a generator via transmission lines of total resistance 3.0 Ω, calculate (a) the emf at the generator end of the lines, and (b) the fraction of the power generated that is wasted in the lines.
1956
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교과서 질문
(II) For the electric power transmission system shown in Fig. 29–26, what is the ratio Ns/Np for (a) the step-up transformer, (b) the step-down transformer next to the home?
1668
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교과서 질문
(III) In a circular region, there is a uniform magnetic field pointing into the page (Fig. 29–56). An xy coordinate system has its origin at the circular region’s center. A free positive point charge +Q = 1.0 μC is initially at rest at a position x = +10 cm on the x axis. If the magnitude of the magnetic field is now decreased at a rate of -0.10 T/s, what force (magnitude and direction) will act on +Q?
1211
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교과서 질문
A transformer has 680 turns in the primary coil and 85 in the secondary coil. What kind of transformer is this, and by what factor does it change the voltage? By what factor does it change the current?
1569
views