Question regarding alternating current

In summary, the mean power dissipated in a resistor when an a.c. flows through it is P. If the frequency of the a.c. is doubled while the peak voltage remains the same, the average power dissipated remains the same at P. This is because the root mean square voltage, which is derived from mean power considerations, is independent of frequency as long as the peak voltage remains the same. However, in circuits with inductance, the current is limited by inductive reactance which is frequency dependent.
  • #1
Sanosuke Sagara
102
0
When an a.c. flows in a resistor,the mean power dissipated is P.If the frequency of the a.c. is doubled with the same value of peak voltage,what id the average power dissipated now ?

My solution :

P = (I_rms)^2 R

I assume that as the peak voltage remains the same and the mean power value doesn't influenced by the frequency of the a.c. , so the mean power remains the same, that is P.

Is my assumption right ?I hope that someone will help me figure out.Do comment if I have any error in my assumption.Thanks for anybody that spend some time on this question.
 
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  • #2
The root mean square voltage is derived from mean power considerations. Hence it is independent of the frequency. As long as the peak voltage is the same, the r.m.s. voltage is the same, and hence the mean power output is the same.
 
  • #3
Sanosuke Sagara said:
I assume that as the peak voltage remains the same and the mean power value doesn't influenced by the frequency of the a.c. , so the mean power remains the same, that is P.

Is my assumption right ?
Your assumption is correct, in a circuit with no inductance. Inductive reactance, which limits current, is frequency dependent.

AM
 

1) What is alternating current (AC)?

Alternating current is a type of electrical current that periodically reverses direction. This means that the flow of electrons alternates back and forth, rather than flowing in one direction like in direct current (DC).

2) How does alternating current work?

Alternating current is created by using a device called an alternator, which converts mechanical energy into electrical energy. The alternator consists of a rotating coil of wire inside a magnetic field, which induces a current in the wire as it rotates.

3) What is the difference between alternating current and direct current?

The main difference between AC and DC is the direction of electron flow. In AC, the direction of flow constantly changes, while in DC, the flow remains in one direction. AC is also able to travel longer distances without significant power loss, making it more practical for use in large-scale power grids.

4) Why is alternating current used in homes and buildings?

AC is used in homes and buildings because it can be easily converted to different voltages using a transformer, making it more versatile for different appliances and devices. AC also allows for more efficient transmission of electricity over long distances.

5) Are there any disadvantages to using alternating current?

One of the main disadvantages of AC is that it can cause electrical interference in electronic devices. It can also be more dangerous than DC, as the constant changes in direction can make it more difficult to control in certain situations. Additionally, the conversion process from AC to DC can result in energy loss.

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