Question about AC, frequency, and watts.

Hi:

Let's say there are two AC [Alternating Current] signals of the same
voltage and amperage. However, one of them is 50 Hz and the other is
60 Hz.

Will the 60 Hz signal contain more watts than the 50 Hz signal?

I ask because...

... let's say there are two equally-large laser beams which contain
the same light intensity [i.e. number of photon[s]-per-second-per-
square-meter]. If one beam is of 400 nm wavelength and the other is
700 nm, the 400 nm light beam will contain more watts than the 700 nm
one because a shorter-wavelength [i.e. higher-frequency] photon
possesses more energy in it than a longer-wavelength [or lower-
frequency] photon.

I am wondering if the same analogy applies to electric current.


Thanks



no.




no.


sure, anytime




The average power dissipated is I^2R where I is the rms current and R
is the real part of the load (assuming the load is complex ie with
inductance). So if both rms currents are the same (which you said they
were) and R is the same then the power is the same. Average power is
also given by VIcos(phi) where V and I are both rms voltage and
current and cos(phi) is the power factor ie phi is the angle bewteen V
and I. This gives the same answer as previous.

However, if two ac voltages of the same rms value but different
frequencies are applied to a load R+jwL

where R is resistance L is inductance and w is 2pif rads/s then the
current for each case will be different.

rms current I=3DV/sqrt(R^2+(wL)^2) and hence I will be smaller if w is
larger and hence the power will be smaller.
So a larger freq dissipates smaller power for a given load. The power
for both cases will be

P =3DR . V^2/(R^2+(wL)^2)



Hardy


It doesn't if you measuring what's called apparent power.
But, with AC lines people usually think in terms of RMS power.
It which case the frequency doesn't have anything to do with power
throughput.








wrote:


Which is why real scientists and engineers spend their time working on
perpetual motion machines, free energy, channeled schematic diagrams,
UFO tracking, debunking relativity, time travel, ghost busting, aether
theory, faster than light communications, warp drives, etc. ...

Idiot.

(Not because your answer is wrong, but because you responded to
GreenXenon at all! )