Advertisements
Advertisements
प्रश्न
A light bulb is rated at 125 W for a 250 V a.c. supply. Calculate the resistance of the bulb.
उत्तर
Power of the bulb, P = 125 W, Voltage, V = 250 V
The resistance of the bulb is given as `R = V^2/P = 250^2/125 = 500 Ω`
APPEARS IN
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.
Draw a graph to show variation of capacitive-reactance with frequency in an a.c. circuit.
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 and a solenoid are connected in series across an ac source of voltage. Explain, how the glow of the light bulb will be affected when an iron rod is inserted in the solenoid.
An AC source is connected to a capacitor. Will the rms current increase, decrease or remain constant if a dielectric slab is inserted into 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`) .
Which of the following graphs represents the correct variation of inductive reactance XL with frequency u?
In a pure capacitive circuit if the frequency of ac source is doubled, then its capacitive reactance will be ______.
Which of the following graphs represents the correct variation of capacitive reactance Xc with frequency v u?
