Question types

Alternating Current question types

49 questions across 6 question groups — pick any mix to generate a Physics paper with step-by-step answer keys.

49
Questions
6
Question groups
5
Question types
Sample Questions

Alternating Current questions

One sample from each question group in this chapter. Select any group above to see the full set with answer keys.

The AC voltage across a resistance can be measured using:
  • A
    A potentiometer.
  • A hot-wire voltmeter.
  • C
    A moving-coil galvanometer.
  • D
    A moving-magnet galvanometer.

Answer: B.

View full solution
An $AC$ source rated $100V (rms)$ supplies a current of $10A (rms)$ to a circuit. The average power delivered by the source:
  1. Must be $1000W.$
  2. May be $1000W.$
  3. May be greater than $1000W.$
  4. May be less than $1000W.$
  • A
    $A$ and $B$
  • B
    $B$ and $C$
  • $B$ and $D$
  • D
    $C$ and $D$

Answer: C.

View full solution
An $AC$ source is rated $220V, 50Hz.$ The average voltage is calculated in a time interval of $0.01s,$ It:
  • A
    Must be zero.
  • May be zero.
  • C
    Is never zero.
  • D
    Is $\Big(\frac{200}{\sqrt{2}}\Big)\text{V}.$

Answer: B.

View full solution
In an $AC$ series circuit, the instantaneous current is zero when the instantaneous voltage is maximum. Connected to the source may be a:
  • A
    Pure inductor.
  • B
    Pure capacitor.
  • C
    Combination of an inductor and a capacitor.
  • All of the above

Answer: D.

View full solution
When an AC source is connected to a capacitor there is a steady-state current in the circuit. Does it mean thatthe charges jump from one plate to the other to complete the circuit?
View full solution
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?
View full solution
In a circuit containing a capacitor and an AC source the current is zero at the. stant the source voltage is maximum. Is it consistent with Ohm's law?
View full solution
A transformer is designed to convert an AC voltage of 220V to an AC voltage of 12V. If the input terminals are connected to a DC voltage of 220V, the transformer usually burns. Explain.
View full solution
The peak power consumed by a resistive coil, when connected to an AC source, is 80W. Find the energy consumed by the coil in 100 seconds, which is many times larger than the time period of the source.
View full solution
The current in a discharging LR circuit is given by $\text{i}=\text{i}_0\text{e}^{\frac{-\text{t}}{\tau}}$ where $\tau$ is the time constant of the circuit. Calculate the rms current for the period $\text{t}=0$ to $\text{t}=\tau.$
View full solution
A resistance is connected to an AC source. If a capacitor is included in the series circuit, will the average power absorbed by the resistance increase or decrease? If an inductor of small inductance is also included in the series circuit, will the average power absorbed increase or decrease further?
View full solution
The dielectric strength of air is $3.0 \times 10^6 \mathrm{~V} / \mathrm{m}$. A parallel-plate air-capacitor has area $20 \mathrm{~cm}^2$ and plate separation 0.10 mm . Find the maximum rms voltage of an AC source that can be safely connected to this capacitor.
View full solution
Q 163 Marks Question3 Marks
An inductor-coil, a capacitor and an AC source of rms voltage 24V are connected in series. When the frequency of the source is varied, a maximum rms current of 6.0A is observed. If this inductor coil is connected to a battery of emf 12V and internal resistance $4.0\Omega,$ what will be the current?
View full solution
Q 183 Marks Question3 Marks
A bulb rated 60W at 220V is connected across a household supply of alternating voltage of 220V. Calculate the maximum instantaneous current through the filament.
View full solution
Q 193 Marks Question3 Marks
Consider the situation of the previous problem. Find the average electric field energy stored in the capacitor and the average magnetic field energy stored in the coil.
View full solution
Q 203 Marks Question3 Marks
A coil of inductance $5.0\ mH$ and negligible resistance is connected to the oscillator of the previous problem. Find the peak currents in the circuit for $\omega=100\text{s}^{-1},500\text{s}^{-1},1000\text{s}^{-1}.$
View full solution
A resistor of resistance $100\Omega$ is connected to an AC source $\in=(12\text{V})\sin(250\pi\text{s}^{-1})\text{t}.$ Find the energy dissipated as heat during $\text{t}=0$ to $\text{t}=1.0\text{ms}.$
View full solution
A capacitor of capacitance $10\mu\text{F}$ is connected to an oscillator with output voltage $\in=(10\text{V})\sin\omega\text{t}.$ Find the peak currents in the circuit for $\omega=10\text{s}^{-1},100\text{s}^{-1},500\text{s}^{-1},1000\text{s}^{-1}.$
View full solution
A coil has a resistance of $10\Omega$ and an inductance of 0.4 henry. It is connected to an AC source of $6.5\text{V},\frac{30}{\pi}\ \text{Hz}$ Find the average power consumed in the circuit.
View full solution
An electric bulb is designed to consume 55W when operated at 110 volts. It is connected to a 220V, 50Hz line through a choke coil in series. What should be the inductance of the coil for which the bulb gets correct voltage?
View full solution
An inductance of 2.0H, a capacitance of $18\mu\text{F}$ and a resistance of $10\text{K}\Omega$ are connected to an AC source of 20V with adjustable frequency.
  1. What frequency should be chosen to maximise the current in the circuit?
  2. What is the value of this maximum current?
View full solution
The household supply of electricity is at 220V (rms value) and 50Hz. Find the peak voltage and the least possible time in which the voltage can change from the rms value to zero.
View full solution

Generate a Alternating Current paper free

Pick question groups from the list above, set marks and difficulty, and export a branded PDF with step-by-step answer keys. First 3 chapters free — no signup.

Download App