Question

Q4. A science project exhibit, a capacitor is connected in series with a bulb connected to an ac source. If its voltage amplitude is held constant, choose the correct option for the light bulb to glow the brightest at (a) high frequencies (b) low frequencies (c) The brightness will be same at all frequencies. At what frequency the light bulb will glow the dimmest, if capacitor is replaced by inductor? When an AC source is replaced by DC source find out whether the bulb will glow or not in both cases? Justify your answer scientifically. In the above circuit 4.4 μF capacitor in series with light bulb of resistance 1.5 kΩ connected to 240 V, 50 Hz? How can you evaluate the r.m.s value of current through the entire circuit? Can you find the average power developed across the entire circuit? When the capacitor is replaced by the inductor of 450 mH, how can you predict the r.m.s current and average power in that circuit? In an LCR series circuit, when capacitive reactance and inductive reactance are equal then what would be the r.m.s current flowing in the circuit? Prove this r.m.s current higher than r.m.s current in LR and CR circuits calculated in above cases? Justify your answer..

Answer #1

A circuit contains a light bulb and a capacitor (RC circuit) in
series connected to an AC power supply. How should you choose the
AC frequency such that the light glow the brightest? Why?

An AC voltage source is connected in series to an inductor, a
capacitor, and a resistor of 5 Ohms. At the frequency when the
phase angle is zero, capacitive reactance is 6 Ohms. What is the
total impedance of the of the circuit at a frequency which is a
factor of 2.4 times less than this frequency? Answer in Ohms.

An AC power supply is connected in series with a light bulb, a
capacitor, and an ammeter.
a) Would the ammeter measure a current? Please explain.
b) Can charges flow through the capacitor, i.e. go from on plate
to the other plate through the dielectric? Please
explain.

A series AC circuit contains a resistor, an inductor of 210 mH,
a capacitor of 5.50 µF, and a source with ΔVmax = 240 V operating
at 50.0 Hz. The maximum current in the circuit is 200 mA. (a)
Calculate the inductive reactance. Ω (b) Calculate the capacitive
reactance. Ω (c) Calculate the impedance. kΩ (d) Calculate the
resistance in the circuit. kΩ (e) Calculate the phase angle between
the current and the source voltage. °

A capacitor of 20 microF and a resistor of 50 ohms are connected
in series across a 240 V, 50 Hz supply. Calculate: (a) the
capacitive reactance, (b) the circuit impedance, (c) the total
current flow, (d) the potential difference across each element, (e)
the power factor, (f) the average power absorbed by the circuit

] Consider a series RLC circuit.
a) When the capacitor is charged and the circuit is closed, find
the condition for the current to be oscillatory.
b) When the circuit is connected to an AC source V = ?0 cos??, find
the voltage across the inductor and the angular frequency at which
the voltage across the inductor is maximized.

A series ac circuit contains a 350-Ω resistor, a 11.0-mH
inductor, a 3.70-μF capacitor, and an ac power source of voltage
amplitude 45.0 V operating at an angular frequency of 360 rad/s .
What is the power factor of this circuit? Find the average power
delivered to the entire circuit. What is the average power
delivered to the resistor, to the capacitor, and to the inductor?
Enter your answers numerically separated by commas.

A 7.34 µF capacitor and a 7.38 mH inductor are connected in
series with an AC power source that has a frequency of 3.78
x103 Hz and a peak voltage of 76 V. Take the initial
time t as zero when the instantaneous voltage equals zero.
Determine the instantaneous current when t = 5.68x
10-4 s.

1. A light bulb and a parallel plate capacitor (containing a
dielectric material between the plates) are connected in series to
the 60-Hz ac voltage present at a wall outlet. When the dielectric
material is removed from the space between the plates, does the
brightness of the bulb increase, decrease, or remain the same?
2. An inductor and a capacitor are connected in parallel across
the terminals of an ac generator. Does the current from the
generator decrease, remain the...

A 100 Ω resistor, 0.0200 H inductor and 30 x 10-6
F capacitor are connected in series to a 20 V rms AC source. The
frequency of the source can be varied. What is the rms current in
the circuit when the frequency is 250 Hz?

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