physics
posted by Anonymous .
A sinusoidal voltage Δv = (65 V) sin (140t) is applied to a series RLC circuit with L = 100 mH, C = 175 μF, and R = 42 Ω.
(a) What is the impedance of the circuit?

R = 42 Ohms.
Xc = 1/W*C = 1/(140*175*10^6)=40.8 Ohms
Xl = W*L = 140*100*10^3 = 14 Ohms.
Z^2 = R^2 + (XlXc)^2 = 2482.24
Z = 49.82 Ohms.
tanA = (XlXc)/R = (1440.8)/42=0.63810
A = 32.54o = Phase angle.
Z = 49.82 Ohms @ 32.54o.