Which wave will generate more heat?

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In summary, the question of which waveform will generate more heat cannot be accurately answered without specifying the amplitudes and loads. However, assuming all waveforms have the same amplitude and load, the square wave would generate the most heat due to its higher RMS value. It should also be noted that the average power delivered to a resistor is directly related to the RMS value of the waveform. Laser beams, which typically operate at a single frequency, can potentially generate coherent harmonics through frequency-doubling or modulation of the injection current.
  • #1
samieee
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Suppose there are some waveforms to be used as current input: i)sine wave ii)square wave iii) triangle wave iv)sawtooth wave and v)sawtooth wave with both the cycles(+ve half cycle and -ve half cycle) in positive Y axis. Which wave will generate more heat?

Actually, I faced this question in a recent examination. Though I ansewered (v), now I think the right answer would be square wave, as it grabs the maximum magnitude for more duration of time than the others. Am I right?

Thanks.
 
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  • #3
So, from the comparison, I see that square wave has the higher value than any other rotating wave. DC shifted square wave has even higher value as it should have.
 
  • #4
samieee said:
So, from the comparison, I see that square wave has the higher value than any other rotating wave. DC shifted square wave has even higher value as it should have.
Right, so your intuition with regards to the square wave was spot on.

The instantaneous power delivered to the resistor is ##p(t) = R i(t)^2##. If you try to imagine the graph of ##p(t)## for your waveforms, it should confirm your idea of why its average value is highest in the case of the square wave.
 
  • #5
samieee said:
Suppose there are some waveforms to be used as current input: i)sine wave ii)square wave iii) triangle wave iv)sawtooth wave and v)sawtooth wave with both the cycles(+ve half cycle and -ve half cycle) in positive Y axis. Which wave will generate more heat?
This question cannot really be answered as stated here. Are the amplitudes of all the waves supposed to be the same? That needs to be specified.
 
  • #6
Redbelly98 said:
Are the amplitudes of all the waves supposed to be the same? That needs to be specified.

Yes, amplitudes of all the waves are same.
 
  • #7
Okay. So yes, it is the square wave. As milesyoung said, you need to consider [itex]i^2 R[/itex].
 
  • #8
Also assuming the loads are the same.
 
  • #9
All the signals have the same frequency?
 
  • #10
Windadct said:
Also assuming the loads are the same.
Yes.

KHMOU YOUSSEF said:
All the signals have the same frequency?
That does not matter. The average of i2 is the same no matter what the frequency is. Just for example, for a sine wave, it is (1/2) the square of the amplitude, independent of the frequency.
 
  • #11
The real question is could you make a saw tooth laser beam if you super imposed different frequencies on top of each other. Not sure how this could be accomplished but its an interesting thought.
 
  • #12
Huh? Lasers operate at one frequency, i.e perfect sine wave oscillation, unless you mean to modulate the laser?
 
  • #13
samieee said:
Suppose there are some waveforms to be used as current input: i)sine wave ii)square wave iii) triangle wave iv)sawtooth wave and v)sawtooth wave with both the cycles(+ve half cycle and -ve half cycle) in positive Y axis. Which wave will generate more heat?
That's the beauty of the RMS value, it directly relates to the heating value (in a resistive load). :smile:
 
  • #14
Windadct said:
Huh? Lasers operate at one frequency, i.e perfect sine wave oscillation, unless you mean to modulate the laser?
Wouldn't frequency-doubling lasers allow you to generate some coherent harmonics?
 
  • #15
or you could modulate the injection current to get a sawtooth amplitude at some frequency << lasing frequency
 

1. What type of waves generate heat?

Electromagnetic waves, such as infrared and visible light, are the types of waves that generate heat.

2. How does the wavelength affect heat generation?

The shorter the wavelength of a wave, the more energy it carries and the more heat it can generate. This is because shorter wavelengths have a higher frequency, which means more energy is transferred per unit of time.

3. Which wave has a higher potential for heat generation: visible light or infrared?

Infrared waves have a higher potential for heat generation compared to visible light. This is because infrared waves have longer wavelengths and lower frequencies, which means they carry more energy and can penetrate deeper into materials, causing more heat to be generated.

4. Can sound waves generate heat?

Yes, sound waves can generate heat, but the amount of heat produced is very small. This is because sound waves have much longer wavelengths and lower frequencies compared to electromagnetic waves.

5. How does the intensity of a wave affect heat generation?

The higher the intensity of a wave, the more heat it can generate. This is because higher intensity waves have more energy and can transfer more heat to the molecules in a material, causing them to vibrate faster and generate more heat.

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