# Lossy Transmission Lines MCQ’s

This set of RF & Microwave Circuit Design Multiple Choice Questions & Answers (MCQs) focuses on “Lossy Transmission Lines”.

1. Expression for α(attenuation constant) in terms of R , G, L and C of a transmission line is:

a) (R√(C/L)+G√(L/C))0.5

b) (R√(C/L)+G√(L/C))

c) (R√(L/C)+G√(C/L))

d) (R√(L/C)+G√(C/L))0.5

2. Expression for characteristic impedance Zₒ of a transmission line in terms of L and C the transmission line is:

a) √(C/L)

b) √(CL)

c) √(L/C)

d) 1/√(LC)

3. For a low loss line when both conductor and di-electric loss is small, the assumption that could be made is:

a) R < < ωL and G < < ωC

b) R > > ωL and G > >ωC

c) R < <ωC and G < < ωL

d) R > >ωC and G > >ωL

4. If the inductance and capacitance of a loss line transmission line are 45 mH/m and10 µF/m, the characteristic impedance of the transmission line is:

a) 50Ω

b) 67.08Ω

c) 100Ω

d) none of the mentioned

5. If R = 1.5Ω/m, G = 0.2 mseimens/m, L = 2.5 nH/m, C = 0.1 pF/m for a low loss transmission line, then the attenuation constant of the transmission line is:

a) 0.0.158

b) 0.0523

c) 0.0216

d) 0.0745

6. The condition for a distortion less line is:

a) R/L=G/C

b) R/C=G/L

c) R=G

d) C=L

7. If the characteristic impedance of a transmission line is 50 Ω, and the inductance of the transmission line being 25 mH/m, the capacitance of the lossy transmission line is:

a) 1µF

b) 10 µF

c) 0.1 µF

d) 50 µF

8. A lossy line that has a linear phase factor as a function of frequency is called:

a) distortion less line

b) terminated lossy line

c) loss less line

d) lossy line

9. For a distortion less line, R= 0.8Ω/m, G= 0.8 msiemens/m, L= 0.01µH/m then C is:

a) 10 pF

b) 1pF

c) 1nF

d) 10nF

10. For a lossy transmission line, γ=0.02+j0.15 and is 20m long. The line is terminated with an impedance of a 400Ω. Then the input impedance of the transmission line given that the characteristic impedance of the transmission line is 156.13+j11.38Ω is:

a) 100+j50 Ω

b) 228+j36.8 Ω

c) 50+36.8j Ω

d) none of the mentioned