Tag: alternating currents

Questions Related to alternating currents

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

physics alternating currents sinusoidal current types of current movement of charge

  1. continuous decrease and increase of current occurs.

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

  3. both

  4. none

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Correct Option: B
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.

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

physics alternating currents sinusoidal current types of current movement of charge

  1. $2.4A$

  2. $1.8A$

  3. $1.5A$

  4. $1.2A$

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Correct Option: C

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:

physics alternating currents sinusoidal current types of current movement of charge

  1. $308\ volts$

  2. $264\ volts$

  3. $220\ volts$

  4. $zero$

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Correct Option: D

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

physics alternating currents sinusoidal current types of current movement of charge

  1. Electroplating

  2. Charging a battery

  3. Charging a capacitor

  4. Electrolysis

  5. Heating a room

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Correct Option: A

Two alternating currents having value $I _{1} = 3\sin \omega t$ and $I _{2} = 4\sin \left (\dfrac {\pi}{2} - \omega \right )$ are superimposed and passed through a hot wire ammeter. Then the roading of ammeter will be

physics alternating currents sinusoidal current types of current movement of charge

  1. $5A$

  2. $-\dfrac {5}{\sqrt {2}}A$

  3. $7A$

  4. $\dfrac {7}{\sqrt {2}}A$

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Correct Option: C

In alternating current

physics alternating currents sinusoidal current types of current movement of charge

  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

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Correct Option: C
Explanation:

C

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

 

An alternating current is that current which changes regularly its

physics alternating currents sinusoidal current types of current movement of charge

  1. Magnitude

  2. Direction

  3. Both a and b

  4. None of the above

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Correct Option: C

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?

physics alternating currents sinusoidal current types of current movement of charge

  1. R

  2. $\frac{R}{2}$

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

  4. 2R

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Correct Option: A