Alternating Current MSQ - Physics MCQ

The frequency

The current at resonance is



The correct answers are: I₀ = 40A , V₀ = 9.8kV, V₁ = 9.8kV

(ε = ε₀ sinωt)

As we know resonating angular  frequency is 

so circuit is in resonance and impedence is made up of only resistance part

The correct answers are: The circuit is at resonance and its impedance is made up only of a reactive part, The sum of the potential differences across the inductance and capacitance equals the applied emf which is 180° ahead of phase of the current in the circuit, Impedance of the circuit is less than R

The correct answers are: both circuits must be having same value of capacitance and inductor, in both circuits ratio of L and C will be same, both circuits must have same impedance at all frequencies.

It is apparent from the graph that emf attains its maximum value before the current does, therefore current lags behind emf in the circuit. Nature of the circuit is inductive.
Value of power factor cos φ increases by either by decreasing L or by increasing C..

The correct answers are: The circuit is more inductive than capacitive., To increase the rate at which energy is transferred to the resistive load, L should be decreased.

= 2A

= 1000 volt
The correct answers are: f = 125 Hz, current through R is 2A, V₁ = V₂ = 1000 Volt

When L and C are in series, voltage across capacitor and inductor is 180º out of phase.

The correct answers are: has current  given by I = V/R has a voltage across the capacitor which is 180° out of phase with that across the inductor

(f = 900 Hz) < (f_res = 1000 Hz), so X_C > X_L, circuit becomes capacitive and current leads emf.
At resistance, impedance in minimum.
Not only at resonance, but at all conditions voltage across L and C differs in phase by 180° when connected in series.

The correct answers are: when f = 900Hz, then the current through the voltage source will be ahead of emf of the source, the impedance of the circuit is minimum at f = 1000Hz

Since the circuit is at resonance so current in the circuit is in the phase with applied voltage. Voltage across inductro leads the current by π/2 and across a capacitor lag by π/2. So the voltage across resistance is lagging by 90^∘ than the voltage across capacitor.

1) DC current will travel through the entirety of the wire -- AC current will tend to move on the outside of the conductor (see Skin Effect). This will cause slightly more ohmic heating in AC than in DC. That's why AC wire is usually stranded while DC wire is usually solid -- more strands = more surface area.

 the time for which the current flows in the conductor, the resistance of the conductor, the strength of the current.

Since V_C < V_L, so circuit is capacitive

The correct answers are: Voltage across resistor, inductor and capacitor are  and   respectively, Power factor of the circuit is 5/13,  The circuit is capacitive in nature