Advertisements
Advertisements
प्रश्न
A light bulb is rated 100 W for 220 V ac supply of 50 Hz. Calculate
(i) The resistance of the bulb;
(ii) The rms current through the bulb.
उत्तर
P = 100 W Vrms = 220 V
(a) Resistance, R
`=V_(rms)^2/P = (220 xx 220)/100 Ω =484Omega`
(b) P = Irms Vrms
`I_(rmo) =P/V_(rms) = (100W)/(220V)` = 0.45A
संबंधित प्रश्न
You are given three circuit elements X, Y and Z. When the element X is connected across an a.c. source of a given voltage, the current and the voltage are in the same phase. When the element Y is connected in series with X across the source, voltage is ahead of the current in phase by π/4 . But the current is ahead of the voltage in phase by π/4when Z is connected in series with X across the source. Identify the circuit elements X, Y and Z. When all the three elements are connected in series across the same source, determine the impedance of the circuit.Draw a plot of the current versus the frequency of applied source and mention the significance of this plot.
Three capacitors of capacities 8 μF, 8 μF and 4 μF are connected in a series and potential difference of 120 volt is maintained across the combination. Calculate the charge on capacitor of capacity 4 μF.
A light bulb is rated at 120 W for a 220 V a.c. supply. Calculate the resistance of the bulb.
A light bulb is rated at 125 W for a 250 V a.c. supply. Calculate the resistance of the bulb.
What is the reactance of a capacitor connected to a constant DC source?
When the frequency of the AC source in an LCR circuit equals the resonant frequency, the reactance of the circuit is zero. Does it mean that there is no current through the inductor or the capacitor?
(i) An alternating emf of 200 V, 50 Hz is applied to an L-R ciruit, having a resistance R of 10 Ω and an inductance L of 0.05H connected in series. Calculate :
(1) Impedance
(2) Current flowing in the circuit
(ii) Draw a labelled graph showing the variation of inductive reactance (`X_L`) verses frequency (`f`) .
A series combination of an inductor (L), capacitor (C) and a resistor (R) is connected across an ac source of emf of peak value E0, and angular frequency (ω). Plot a graph to show variation of impedance of the circuit with angular frequency (ω).
Which of the following graphs represents the correct variation of inductive reactance XL with frequency u?
