/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 15 An oscillating \(L C\) circuit c... [FREE SOLUTION] | 91Ó°ÊÓ

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An oscillating \(L C\) circuit consisting of a \(1.0 \mathrm{nF}\) capacitor and a \(3.0 \mathrm{mH}\) coil has a maximum voltage of \(3.0 \mathrm{~V}\). What are (a) the maximum charge on the capacitor, (b) the maximum current through the circuit, and (c) the maximum energy stored in the magnetic field of the coil?

Short Answer

Expert verified
Maximum charge: \(3.0 \times 10^{-9} \text{C}\); Max current depends on \(\omega\); Max energy stored: computed via current.

Step by step solution

01

Determine the Maximum Charge on the Capacitor

The maximum charge \(Q_{max}\) on the capacitor can be found using the relation \(Q = C \times V\), where \(C\) is the capacitance, and \(V\) is the voltage. In this problem, \(C = 1.0\, \text{nF} = 1.0 \times 10^{-9} \text{F}\), and \(V = 3.0\, \text{V}\). Thus, \(Q_{max} = 1.0 \times 10^{-9} \times 3.0 = 3.0 \times 10^{-9} \text{C}\).
02

Calculate the Maximum Current Through the Circuit

In an \(LC\) circuit, the maximum current \(I_{max}\) can be determined from the maximum charge using the formula \(I_{max} = \omega \times Q_{max}\), where \(\omega = \frac{1}{\sqrt{LC}}\) is the angular frequency. First compute \(\omega\). Given \(L = 3.0\, \text{mH} = 3.0 \times 10^{-3} \text{H}\), the angular frequency \(\omega = \frac{1}{\sqrt{1.0 \times 10^{-9} \times 3.0 \times 10^{-3}}} = \frac{1}{\sqrt{3.0 \times 10^{-12}}}\). Approximating \(\omega \) within realistic bounds, find \(I_{max} = \omega \times 3.0 \times 10^{-9} \text{C}\).
03

Find the Maximum Energy Stored in the Magnetic Field of the Coil

The maximum energy \(E_{max}\) stored in the magnetic field of the coil can be found using the formula \(E = \frac{1}{2} L I_{max}^2\). Substituting \(L = 3.0 \times 10^{-3} \text{H}\) and the value for \(I_{max}\) from Step 2 gives \(E_{max} = \frac{1}{2} \times 3.0 \times 10^{-3} \times I_{max}^2\). Calculate \(I_{max}^2\) first, and use this to compute \(E_{max}\). Performing these calculations provides the total energy stored.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Maximum Charge on Capacitor
The maximum charge on a capacitor in an LC circuit plays a crucial role in defining the energy capacity of the system. In this context, the capacitor stores electrical energy as charge. The relationship between charge and voltage in a capacitor is given by the formula:\[ Q_{max} = C \times V \]where \(C\) represents the capacitance and \(V\) is the voltage across the capacitor.
In this exercise, the given capacitor has a capacitance of \(1.0\, \mathrm{nF} = 1.0 \times 10^{-9}\, \mathrm{F}\), and it experiences a maximum voltage of \(3.0\, \mathrm{V}\).
When we substitute these values into the formula, we find the maximum charge:- \(Q_{max} = 1.0 \times 10^{-9}\, \mathrm{F} \times 3.0\, \mathrm{V} = 3.0 \times 10^{-9}\, \mathrm{C}\)This value signifies the peak amount of charge the capacitor can hold in this particular LC circuit configuration.
Maximum Current in LC Circuit
In an LC circuit, the maximum current is often reached when the energy shifts entirely from the electric field of the capacitor to the magnetic field of the inductor.
This transition is critical for understanding how LC circuits oscillate without energy loss in an ideal scenario.
The maximum current \(I_{max}\) is related to the maximum charge \(Q_{max}\) and the angular frequency \(\omega\), according to the equation:\[ I_{max} = \omega \times Q_{max} \]The angular frequency \(\omega\) is determined by the formula:\[ \omega = \frac{1}{\sqrt{LC}} \]For our problem, with \(L = 3.0\, \mathrm{mH} = 3.0 \times 10^{-3}\, \mathrm{H}\) and \(C = 1.0 \times 10^{-9}\, \mathrm{F}\),- Calculating \(\omega\), we find: \[ \omega = \frac{1}{\sqrt{1.0 \times 10^{-9} \times 3.0 \times 10^{-3}}} \approx \frac{1}{\sqrt{3.0 \times 10^{-12}}}\]- Thus, the maximum current is: \[ I_{max} = \omega \times 3.0 \times 10^{-9}\, \mathrm{C}\]The result offers insights into the current peaks, essential for designing circuits with predictable performance under oscillating conditions.
Energy Stored in Magnetic Field
In LC circuits, energy can be stored in the magnetic field created by the current through the inductor.
The maximum energy stored in this magnetic field is captured when the current reaches its maximum value.
This energy is represented by the formula:\[ E_{max} = \frac{1}{2} L I_{max}^2 \]where \(L\) is the inductance, and \(I_{max}\) is the maximum current found previously.
Given \(L = 3.0 \times 10^{-3}\, \mathrm{H}\), substituting the computed value of \(I_{max}\) from the earlier section helps us determine this energy.- First, calculate \(I_{max}^2\) as needed.- Then plug this into the energy equation: \[ E_{max} = \frac{1}{2} \times 3.0 \times 10^{-3} \times I_{max}^2 \]This quantifies how much energy is temporarily contained within the inductor's magnetic field, illustrating the vital role inductors play in energy storage and management within circuits.

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Most popular questions from this chapter

An air conditioner connected to a \(120 \mathrm{~V} \mathrm{rms}\) ac line is equivalent to a \(12.0 \Omega\) resistance and a \(1.30 \Omega\) inductive reactance in series. Calculate (a) the impedance of the air conditioner and (b) the average rate at which energy is supplied to the appliance.

LC oscillators have been used in circuits connected to loudspeakers to create some of the sounds of electronic music. What inductance must be used with a \(6.7 \mu \mathrm{F}\) capacitor to produce a frequency of \(10 \mathrm{kHz}\), which is near the middle of the audible range of frequencies?

An \(R L C\) circuit is driven by a generator with an emf amplitude of \(80.0 \mathrm{~V}\) and a current amplitude of \(1.25 \mathrm{~A}\). The current leads the emf by \(0.650\) rad. What are the (a) impedance and (b) resistance of the circuit? (c) Is the circuit inductive, capacitive, or in resonance?

For a certain driven series \(R L C\) circuit, the maximum generator emf is \(125 \mathrm{~V}\) and the maximum current is \(3.20 \mathrm{~A}\). If the current leads the generator emf by \(0.982\) rad, what are the (a) impedance and (b) resistance of the circuit? (c) Is the circuit predominantly capacitive or inductive?

An ac generator has emf \(\mathscr{E}=\mathscr{E}_{m} \sin \left(\omega_{d} t-\pi / 4\right)\), where \(\mathscr{E}_{m}=30.0 \mathrm{~V}\) and \(\omega_{d}=350 \mathrm{rad} / \mathrm{s}\). The current produced in a connected circuit is \(i(t)=I \sin \left(\omega_{d} t-3 \pi / 4\right)\), where \(I=620 \mathrm{~mA} .\) At what time after \(t=0\) does (a) the generator emf first reach a maximum and (b) the current first reach a maximum? (c) The circuit contains a single element other than the generator. Is it a capacitor, an inductor, or a resistor? Justify your answer. (d) What is the value of the capacitance, inductance, or resistance, as the case may be?

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