June 4 2009

Hello everybody.
This is Hao. : )
We talk about the answers of the phyz book ( green book) today.

P532
1. EMF=BLV=(4*10^-2 T)(31m)(15m/s)=18.6V

2. EMF=BLV=(0.5 T)( 20m)(4m/s)=40V

3. EMF=BLV=(4.5*10^5 T)(75m)(950000m/3600s)=0.89V

4. a. EMF=BLV=(0.3T)(0.75m)(16m/s)=3.6V
b. I=V/R=3.6V/11Ω=0.33A

5. EMF=BLV=(0.32T)(0.4m)(1.3m/s)=0.17V
I=V/R=0.17V/10Ω=0.017A

14. a. X/150 = 625V/120V
X= 781.25 turns
b. X/150 = 35V/120V
X= 43.75 turns
c. X/150 = 6V/120V
X= 7.5 turns

15. a. X/120v = 1200/80
X=1800V
b. Pp = Ps = (I s)(V s) = (2A)(18000V)=3600w
Ip=Pp/Vp =(3600w)/(120v)=30A
c. Pp=Ps =(Is)(Vs)=(2A)(1800V)=3600W

16. a. X/475 = 9V/120V
X=35.625
b. Ps=(Vs)(Is)=(9v)(0.125A)=1.125W=Pp
Pp= (Vp)(Ip)
Ip=Pp/Vp=1.125w/120v=9.375*10^-3A

P533
20. a. Pp=Ps=150W= (Is)(Vs)=(5A)(Vs)
Vs=150W/5A=30V Bigger than 9V
So, step up
b. 30V/9V = 10/3

21. Pp=(Ip)(Vp)=(3A)(12V)=36W=Ps
Vs=Ps/Is=36W/0.75A=48W
Tp/Ts = Vp/ Vs
Tp= (Vp/Vs)(Ts)=(12V/48V)(1200)=300 turns

we will have unit test tomorrow. good luck everybody......