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

Define Impedance. - Physics

Advertisements
Advertisements

प्रश्न

Define Impedance.

व्याख्या

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 connected to an a.c. source of voltage v = vmsinωt, use phasor diagram to derive an expression for the current in the circuit. Hence, obtain the expression for the power dissipated in the circuit. Show that power dissipated at resonance is maximum


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 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.


A coil of resistance 40 Ω is connected across a 4.0 V battery. 0.10 s after the battery is connected, the current in the coil is 63 mA. Find the inductance of the coil.


An inductor-coil of resistance 10 Ω and inductance 120 mH is connected across a battery of emf 6 V and internal resistance 2 Ω. Find the charge which flows through the inductor in (a) 10 ms, (b) 20 ms and (c) 100 ms after the connections are made.


The current in a discharging LR circuit without the battery drops from 2.0 A to 1.0 A in 0.10 s. (a) Find the time constant of the circuit. (b) If the inductance of the circuit 4.0 H, what is its resistance?


(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.


What will be the potential difference in the circuit when direct current is passed through the circuit? 


Answer the following question.
In a series LCR circuit connected across an ac source of variable frequency, obtain the expression for its impedance and draw a plot showing its variation with frequency of the ac source. 


In a series LCR circuit supplied with AC, ______.


The parallel combination of inductor and capacitor is called as ______.

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 series LCR circuit, the phase angle between supply voltage and current is ______.


At resonance frequency the impedance in series LCR circuit is ______.


The resonant frequency of a RF oscillator is 1 MHz and its bandwidth is 10 kHz. The quality factor will be :


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


A series LCR circuit containing a 5.0 H inductor, 80 µF capacitors, and 40 Ω resistor is connected to a 230 V variable frequency ac source. The angular frequencies of the source at which power is transferred to the circuit are half the power at the resonant angular frequency are likely to be ______.


A series LCR circuit containing 5.0 H inductor, 80 µF capacitor and 40 Ω resistor is connected to 230 V variable frequency ac source. The angular frequencies of the source at which power transferred to the circuit is half the power at the resonant angular frequency are likely to be ______.


If the rms current in a 50 Hz ac circuit is 5 A, the value of the current 1/300 seconds after its value becomes zero is ______.


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


Which of the following combinations should be selected for better tuning of an LCR circuit used for communication?


As the frequency of an ac circuit increases, the current first increases and then decreases. What combination of circuit elements is most likely to comprise the circuit?

  1. Inductor and capacitor.
  2. Resistor and inductor.
  3. Resistor and capacitor.
  4. Resistor, inductor and capacitor.

When an alternating voltage of 220V is applied across device X, a current of 0.25A flows which lags behind the applied voltage in phase by π/2 radian. If the same voltage is applied across another device Y, the same current flows but now it is in phase with the applied voltage.

  1. Name the devices X and Y.
  2. Calculate the current flowing in the circuit when the same voltage is applied across the series combination of X and Y.

A series LCR circuit is connected to an ac source. Using the phasor diagram, derive the expression for the impedance of the circuit.


Three students, X, Y and Z performed an experiment for studying the variation of a.c. 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 220V, 50Hz, and 220V, 100Hz supplies. Find the ratio of current flowing through it in the two cases.

Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×