मराठी
महाराष्ट्र राज्य शिक्षण मंडळएचएससी विज्ञान (सामान्य) इयत्ता १२ वी

Define Impedance. - Physics

Advertisements
Advertisements

प्रश्न

Define Impedance.

व्याख्या
Advertisements

उत्तर

The effective opposition offered by the inductor, capacitor and resistor connected in series to flow of AC current. is called impedance.

Z = `sqrt("R"^2 + (Χ_"L" - Χ_"C")^2)`

shaalaa.com
  या प्रश्नात किंवा उत्तरात काही त्रुटी आहे का?
2021-2022 (March) Set 1

संबंधित प्रश्‍न

In a series LCR circuit, VL = VC ≠ VR. What is the value of power factor?


Why does current in a steady state not flow in a capacitor connected across a battery? However momentary current does flow during charging or discharging of the capacitor. Explain. 


A source of ac voltage v = v0 sin ωt, is connected across a pure inductor of inductance L. Derive the expressions for the instantaneous current in the circuit. Show that average power dissipated in the circuit is zero.


A series LCR circuit is connected to an ac source. Using the phasor diagram, derive the expression for the impedance of the circuit. Plot a graph to show the variation of current with frequency of the source, explaining the nature of its variation.


The time constant of an LR circuit is 40 ms. The circuit is connected at t = 0 and the steady-state current is found to be 2.0 A. Find the current at (a) t = 10 ms (b) t = 20 ms, (c) t = 100 ms and (d) t = 1 s.


An L-R circuit has L = 1.0 H and R = 20 Ω. It is connected across an emf of 2.0 V at t = 0. Find di/dt at (a) t = 100 ms, (b) t = 200 ms and (c) t = 1.0 s.


An LR circuit contains an inductor of 500 mH, a resistor of 25.0 Ω and an emf of 5.00 V in series. Find the potential difference across the resistor at t = (a) 20.0 ms, (b) 100 ms and (c) 1.00 s.


A coil having an inductance L and a resistance R is connected to a battery of emf ε. Find the time taken for the magnetic energy stored in the circuit to change from one fourth of the steady-state value to half of the steady-state value.


Consider the circuit shown in figure. (a) Find the current through the battery a long time after the switch S is closed. (b) Suppose the switch is again opened at t = 0. What is the time constant of the discharging circuit? (c) Find the current through the inductor after one time constant.


(i) An a.c. source of emf ε = 200 sin omegat is connected to a resistor of 50 Ω . calculate : 

(1) Average current (`"I"_("avg")`)

(2) Root mean square (rms) value of emf 

(ii) State any two characteristics of resonance in an LCR series circuit. 


An ac circuit as shown in the figure has an inductor of inductance L and a resistor or resistance R  connected in series. Using the phasor diagram, explain why the voltage in the circuit will lead the  current in phase.


The potential difference across the resistor is 160V and that across the inductor is 120V. Find the  effective value of the applied voltage. If the effective current in the circuit be 1.0 A, calculate the total impedance of the circuit.


In a series, LCR circuit, obtain an expression for the resonant frequency.


Use the expression for Lorentz force acting on the charge carriers of a conductor to obtain the expression for the induced emf across the conductor of length l moving with velocity v through a magnetic field B acting perpendicular to its length.


For a series LCR-circuit, the power loss at resonance is ______.


In an L.C.R. series a.c. circuit, the current ______.


A coil of 40 henry inductance is connected in series with a resistance of 8 ohm and the combination is joined to the terminals of a 2 volt battery. The time constant of the circuit is ______.


In a series LCR circuit the voltage across an inductor, capacitor and resistor are 20 V, 20 V and 40 V respectively. The phase difference between the applied voltage and the current in the circuit is ______.


To reduce the resonant frequency in an LCR series circuit with a generator


The phase diffn b/w the current and voltage at resonance is


For an LCR circuit driven at frequency ω, the equation reads

`L (di)/(dt) + Ri + q/C = v_i = v_m` sin ωt

  1. Multiply the equation by i and simplify where possible.
  2. Interpret each term physically.
  3. Cast the equation in the form of a conservation of energy statement.
  4. Integrate the equation over one cycle to find that the phase difference between v and i must be acute.

A series LCR circuit driven by 300 V at a frequency of 50 Hz contains a resistance R = 3 kΩ, an inductor of inductive reactance XL = 250 πΩ, and an unknown capacitor. The value of capacitance to maximize the average power should be ______.


A series LCR circuit containing a resistance of 120 Ω has angular resonance frequency 4 × 105 rad s-1. At resonance the voltage across resistance and inductance are 60 V and 40 V respectively. At what frequency the current in the circuit lags the voltage by 45°. Give answer in ______ × 105 rad s-1.


Which of the following statements about a series LCR circuit connected to an ac source is correct?


Draw a labelled graph showing variation of impedance (Z) of a series LCR circuit Vs frequency (f) of the ac supply. Mark the resonant frequency as f0·


Three students, X, Y and Z performed an experiment for studying the variation of ac with frequency in a series LCR circuit and obtained the graphs as shown below. They all used

  • an AC source of the same emf and
  • inductance of the same value.

  1. Who used minimum resistance?
  2. In which case will the quality Q factor be maximum?
  3. What did the students conclude about the nature of impedance at resonant frequency (f0)?
  4. An ideal capacitor is connected across 220 V, 50 Hz, and 220 V, 100 Hz supplies. Find the ratio of current flowing through it in the two cases.

In a series LCR circuit, the inductance L is 10 mH, capacitance C is 1 µF and resistance R is 100Ω. The frequency at which resonance occurs is ______.


A series LCR circuit (L = 10 H, C = 10 µF, R = 50 Ω) is connected to V = 200 sin⁡ (100t). If ν0​ is the resonant frequency and ν is the source frequency, then ______.


A resistance of 200Ω and an inductor of \[\frac {1}{2π}\]Н are connected in series to a.c. voltage of 40 V and 100 Hz frequency. The phase angle between the voltage and current is ______.


To an ac power supply of 220 V at 50 Hz, a resistor of 20 Ω, a capacitor of reactance 25 Ω and an inductor of reactance 45 Ω are connected in series. The corresponding current in the circuit and the phase angle between the current and the voltage is respectively:


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×