please convert to the right unit i have submitted this answer before and it was

Question

please convert to the right unit i have submitted this answer before and it was wrong because they didnt convert it right

An RLC series circuit has a 180 ? resistor and a 25.0 mH inductor. At 7600 Hz, the phase angle is 45.0°.

(a)

What is the impedance (in ohms)? ?

(b)

Find the minimum possible capacitance (in nanofarads) of the circuit.

  nf

(c)

If

Vrms = V

is applied, what is the average power (in watts) supplied?

  W

he lowest frequency in the FM radio band is 87.5 MHz.

(a)

What inductance (in µH) is needed to produce this resonant frequency if it is connected to a 2.45 pF capacitor?

µH

(b)

The capacitor is variable, to allow the resonant frequency to be adjusted to as high as 108 MHz. What must the capacitance be (in pF) at this frequency?

pF

Explanation / Answer

Inductive reactance

XL=2pifL =2pi*7600*(25*10-3)

XL=1193.805 ohms

Power factor

Cos(45)=R/Z

=>Z=180/Cos(45)

Z=254.56 ohms

b)

Since Impedance is

Z=sqrt[R2+(XL-XC)2]

254.56 =sqrt[1802 + (1193.805-XC)2]

XC=1013.805 ohms

SInce XC =1/2pifC

=>C=1/2pi*7600*1013.805

C=20.66 nF

c)

Vrms value is not given

Current

I=V/Z

Average Power

Pav=VICos(o) =VICos45

substitute value and get the Pav Value

--------------------------------------------------------------------------------------

a)

Resonant frequency

f=1/2pisqrt(LC)

=>L=1/4pi2f2C =1/4pi2*(87.5*106)2*(2.45*10-12)

L=1.35 uH

b)

Capacitance is

C=1/4pi2f2L =1/4pi2*(108*106)2*(1.35*10-6)

C=1.6086 pF

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