Finding impedance and peak voltage in an RLC circuit

[mmmboh]

Hi here is the problem:

What I did was Z=[(X_L-X_c)²+R²]^1/2 = 5 ohm

and then V/R = I = 110(2)^1/2/5=31.1A

For part B) I did V=L(di/dt)=-Lwsin(wt), and the peak amplitude is when sin(wt)=-1 and is 377V.

Can someone tell me if what I did is right, or what is wrong?

Thanks.

 

[kuruman]

What I did was Z=[(X_L-X_c)²-R²]^1/2 = 5 ohm

and then V/R = I = 110(2)^1/2/5=31.1A

For part B) I did V=L(di/dt)=-LWsin(wt), and the peak amplitude is when sin(wt)=-1 and is 377V.

Your impedance formula is incorrect. Also, what value did you use for ω?

 

[mmmboh]

Sorry I meant +R not -R..but I used the right formula when calculating the value of 5. For w I used 2(pi)f=377 Hz

 

[kuruman]

Looks OK then. I assume that you plugged in the numbers and got X_C and X_L correctly.

 

[mmmboh]

I did (wL-1/(wC)^2 for X_L-X_c

 

[kuruman]

That's fine. I hope you plugged in correctly.