Advertisements
Advertisements
प्रश्न
Obtain the expression for the applied emf and the effective resistance of the circuit when alternating emf is applied to a CR circuit.
उत्तर
- Consider an alternating e.m.f. applied to a series combination of the pure capacitor of capacitance C and resistor of resistance R.
- Let eR and eC be the r.m.s. the voltage across the resistor and capacitor respectively. As R and C are in series, the current at any instant is given as i = i0 sin ωt.
- Vector diagram,
- From the above figure,
e2 = `"e"_"R"^2 + "e"_"C"^2`
∴ e = `sqrt("e"_"R"^2 + "e"_"C"^2) = sqrt(("iR")^2 + ("iX"_"C")^2) = "i"sqrt("R"^2 + "X"_"C"^2)`
∴ e = iZ
where Z = `sqrt("R"^2 + "X"_"C"^2)` is the impedance of the RC circuit. - a. Expression for applied emf in CR circuit,
e = e0sinωt = `sqrt("e"_"R"^2 + "e"_"C"^2)` = iZ
b. Expression for effective resistance in CR circuit, Z = `sqrt("R"^2 + "X"_"C"^2)`
संबंधित प्रश्न
Choose the correct option.
If the rms current in a 50 Hz AC circuit is 5A, the value of the current 1/300 seconds after its value becomes zero is ______.
In an AC circuit, e and i are given by e = 150 sin(150t)V and i = 150 sin `(150t + π/3)` A. The power dissipated in the circuit is ______.
An electric lamp is connected in series with a capacitor and an AC source is glowing with a certain brightness. How does the brightness of the lamp change on increasing the capacitance?
An electric current in an LC – circuit at resonance is called - ______
If AC voltage is applied to a pure capacitor, then the voltage across the capacitor ______
An electric bulb operates 10 V d.c. If this bulb is connected to an a.c. source and gives normal brightness, then the peak value of the source is ______
A coil of resistance 300Ω and inductance 1.0 H is connected across an alternating voltage of frequency `300/(2pi)` Hz, therefore phase difference between the voltage and current in the circuit is ______
Define capacitive reactance.
State the equation for impedance Z in an A.C. circuit.
If the peak value of an alternating emf is 15V, what is its mean value over half cycle?
A series LCR circuit has resistance 10Ω and reactance is `7sqrt2` Ω. What is the impedance of the circuit?
What is the capacitive reactance of a capacitor of 5µF at a frequency of (1) 50 Hz and (2) 20KHZ?
What is the inductive reactance of a coil of inductance 10mH at a frequency
- 50 Hz
- 1000 Hz
- 20 kHz?
Explain the term inductive reactance. State its unit and dimensions.
Obtain the expression for the applied emf and the effective resistance of the circuit when alternating emf is applied to an LR circuit.
The standard voltage of A.C. mains in India is ______
For circuit shown in figure IE = 4 mA, IB = 40 µA. What are the values of ex, and le respectively?
In amplitude modulation. the amplitude of carrier wave is Ac and that of the modulating signal is Am· In practice, the ratio of Am to Ac is kept less than or equal to one, to avoid ______.
An RC Circuit as shown in the figure is driven by a AC source generating a square wave. The output wave pattern monitored by CRO would look close to:
