- #1

Physicslearner500039

- 124

- 6

- Homework Statement
- An electric hair dryer is rated at 1500 W (the average power) at 120 V (the rms voltage). Calculate (a) the resistance, (b) the rms current, and (c) the maximum instantaneous power. Assume that

the dryer is a pure resistor. (The heating element acts as a resistor.)

- Relevant Equations
- P = ##V_{rms}*I_{rms} ##

It is an example problem and i could understand the solution and the answers are

## R = \frac {V_{rms}^2} {P_{av} } = 9.6 \Omega##

##I_{rms} = \frac {P_{av}} {V_{rms}} = 12.5 A##

##p_{max} = VI = 2P_{av} = 3000 W##

But main problem is the statement given by the author below the solution which says "

## R = \frac {V_{rms}^2} {P_{av} } = 9.6 \Omega##

##I_{rms} = \frac {P_{av}} {V_{rms}} = 12.5 A##

##p_{max} = VI = 2P_{av} = 3000 W##

But main problem is the statement given by the author below the solution which says "

*Some unscrupulous manufacturers of stereo amplifiers advertise the peak power output rather than the lower average value*". My understanding is something like the output power is a sine wave, since it is a pure resistance circuit the power keeps fluctuating from min value to max value and the user should actually feel the sound decreasing from min to max sine wave value. Is it correct? Can i clamp the output power coming from the speaker that is the audio to always generate Peak value (3000 W)? The manufacturer should specify the average power or the peak power? Please advise.