Tag: sinusoidal current

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Questions Related to sinusoidal current

Multiple choice physics alternating currents sinusoidal current types of current movement of charge

Why the current produced by the generator is  called as alternating current.

  1. continuous decrease and increase of current occurs.

  2. after every half cycle direction of flow of current is reversed.

  3. both

  4. none
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

We may say that after every half cycle direction of flow of current is reversed. Because of this reason the current produced by the generator is also called as alternating current.

Multiple choice physics alternating currents sinusoidal current types of current movement of charge

A coil, a capacitor and an ac source of rms voltage $24V$ are connected in series. By varying the frequency of the source, a maximum rms current of $6A$ is observed. If this coil is connected to a battery of emf $12V$ and internal resistance $4\Omega$, the current through will be

  1. $2.4A$
  2. $1.8A$
  3. $1.5A$
  4. $1.2A$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

At resonance, the impedance Z = R. Since V_rms = 24V and I_rms = 6A, R = 24/6 = 4 ohms. When connected to a 12V battery with 4 ohms internal resistance, the total resistance is 4+4 = 8 ohms. Current = V/R_total = 12/8 = 1.5A.

Multiple choice physics alternating currents sinusoidal current types of current movement of charge

A mixer of $1000\Omega$ resistance is connected to an $A.C.$ source of $200\ volts$ and $50\ cycle/sec$. The value of average potential difference across the mixer will be:

  1. $308\ volts$
  2. $264\ volts$
  3. $220\ volts$
  4. $zero$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The average value of a symmetric alternating current (like a sine wave) over one full cycle is zero, as the positive and negative half-cycles cancel each other out.

Multiple choice physics alternating currents sinusoidal current types of current movement of charge

Choose the correct statements from the following $A.C.$ cannot be used in

  1. Electroplating

  2. Charging a battery

  3. Charging a capacitor

  4. Electrolysis

  5. Heating a room
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Electroplating and electrolysis require a constant unidirectional current (DC) to ensure metal ions are deposited consistently on the cathode. AC would cause the ions to oscillate back and forth, preventing successful plating.

Multiple choice physics alternating currents sinusoidal current types of current movement of charge

In alternating current

  1. The direction of current is always positive

  2. The direction of current is always negative

  3. The direction of current changes constantly

  4. The direction of current is either positive or negative
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

C

Electric charge in alternating current (AC) changes direction periodically. The voltage in AC circuits also periodically reverses because the current changes direction.

 

Multiple choice physics alternating currents sinusoidal current types of current movement of charge

In an A.C. circuit a resistance R is connected in series with an inductance L.The phase difference between voltage and current is $45^o$. Then what will be the value of inductive reactance?

  1. R
  2. $\frac{R}{2}$
  3. $\frac{R}{4}$

  4. 2R
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In an R-L series circuit, the phase difference is given by tan(phi) = X_L / R. Since phi = 45 degrees, tan(45) = 1, which implies X_L / R = 1, or X_L = R.