Question

The power of a certain CD player operating at 120 V rms is 20.0 W. Assuming that the CD player behaves like a pure resistance, find

(a) the maximum instantaneous power (40 W)
(b) the rms current.
(c) the resistance of this player.

Answer 1

(a) Maximum instantaneous power P = 40 watt

(b) Rms current will be 0.166 A

(C) Resistance will be 720 ohm

Step-by-step explanation:

We have given CD player is operating power V = 120 volt and P = 20 watt

First we calculate the (c) part so that we can we use the value of resistance

(c) We know that power is given by

`P=(V_(rms)^2)/(R)`

`20=(120^2)/(R)`

`R=720\Omega`

(B) Rms current is given by

Current
`i=(V_(RMS))/(R)=(120)/(720)=0.166`

(B) Now maximum instantaneous power is given by

`P=I_0^2R`

`i_0=√(2)i_(rms)=1.414* 0.166=0.2356A`

So power
`P=0.2356^2* 720=40watt`