/*! 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} Q46P An alternating emf source with a... [FREE SOLUTION] | 91影视

91影视

An alternating emf source with a variable frequency fd is connected in series with aR=50.0 resistor and aC=20渭贵 capacitor. The emf amplitude ism=12.0V . (a) Draw a phasor diagram for phasorVR (the potential across the resistor) and phasor VC(the potential across the capacitor). (b) At what driving frequencyfd do the two phasors have the same length? At that driving frequency, what are (c) the phase angle in degrees, (d) the angular speed at which the phasors rotate, and (e) the current amplitude?

Short Answer

Expert verified
  1. Phasor diagram is shown below in the calculation section.
  2. Driving frequency, when both the phasors have same length, isfd=159Hz
  3. Phase angle,when both the phasors have same length, is=-45
  4. Angular speed of rotation of phasor,when both the phasors have same length, isd=1.0103rad/s
  5. Current amplitude,when both the phasors have same length, isI=170mA

Step by step solution

01

Given Data

  1. Resistance, R=50.0
  2. Capacitance,C=20渭贵=2010-6F
  3. Amplitude of emf, m=12.0V
02

Concept

An electric circuit composed of a resistor and capacitor connected in series, is known as a RC circuit. By equating the phasor lengths for VRand Vc, we can find thedriving frequency. By using the formula for phase angle in RCcircuit, we can find the phase angle corresponding to the driving frequency. We can find the angular speed of rotation of phasor by substituting the driving frequency in the formula for angular speed. We can find the current amplitude I in a series RCcircuit by using its formula.

The angular frequency,

d=2fd ...(1)

The capacitive reactance of the capacitor,

XC=1dC ...(2)

The current equation using Ohm鈥檚 law,

I=mZ ...(3)

The impedance of theLCRcircuit for the driving frequency,

Z=R2+Xc2 鈥(4)

Phase angle for series circuit,

=tan-1-cR 鈥(5)

Here, R is the resistance of the resistor, Cis the capacitance of the capacitor, mis the emf in the circuit and fdis the frequency.

03

Calculations

(a) The phasor diagram for VR and VCis shown below:

VClags behind VR by the phase angle 2rad

(b) We have to find the driving frequency at which VRand VChave the same length or amplitude. Therefore,

VR=VC ...(6)


Thus,using equations (1), (2) and (6), we get-

R=ICIR=IdCIR=I2fdC

Rearranging the terms,

fd=12RC


For the given values, we have-

fd=12502010-6Ffd=159Hz

The driving frequency of two phasors is fd=159Hz.


(c) Phase angle for series RC circuit is given by

=tan-1-VCVR

But we have, VR=VC, hence we get,

=tan-1-1=-4rad=-45

The phase angle is given by =-45

(d) Angular speed of rotation of phasor is

d=2fdd=2159Hzd=999.03rad/s1.0103rad/s

(e) Current amplitude in a RC circuit is given by

I=mZ=mR2+C2

SinceR=C,

I=m2C2=m2c=mdC2

I=12.0V1.0103rad/s2010-6F2=170mA

Maximum value of current in RC circuit is 170mA.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91影视!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

A coil of inductanceand 88mHunknown resistance and a 0.94渭贵capacitor are connected in series with an alternating emf of frequency 930Hz. If the phase constant between the applied voltage and the current is 75, what is the resistance of the coil?

A 1.50渭贵capacitor is connected, as in the Figure to an ac generator with m=30.0V. (a) What is the amplitude of the resulting alternating current if the frequency of the emf is1.00kHz? (b) What is the amplitude of the resulting alternating current if the frequency of the emf is 8.00kHz?

What values of phase constant in Eq. 31-12 allow situations (a), (c), (e), and (g) of Fig. 31-1 to occur at t=0?

An ac generator has emf =msin(dt-4), wherem=30V andd=350rad/s. The current produced in a connected circuit isi(t)=Isin(dt-34), where I=620mA. At what time after t=0does (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?

Figure shows an 鈥渁utotransformer.鈥 It consists of a single coil (with an iron core). Three taps Ti are provided. Between taps T1 and T2 there are 200 turns, and between taps T2 and t3 there are800turns. Any two taps can be chosen as the primary terminals, and any two taps can be chosen as the secondary terminals. For choices producing a step-up transformer, (a)What is the smallest? (b)What is the second smallest? (c) What is the largest value of the ratio Vs/Vp? (d) For a step-down transformer, what is the smallest?(e)For a step-down transformer, what is the second smallest? (f) For a step-down transformer, what are the largest values of Vs/Vp?

See all solutions

Recommended explanations on Physics Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.