Transmission Lines
High Frequency
Solved Example: 9910-01
For a transmission line if $\dfrac{L}{C} = \dfrac{R}{G}$, then which of the following is incorrect? (UPPSC AE Electrical Dec 2020)
A. $Z_0^2 = \dfrac{R}{G}$
B. The line is called as distortionless line
C. If a series of pulses are transmitted they arrive undistorted.
D. The line is lossless
Correct Answer: D
Solved Example: 9910-02
A single-phase transmission line of impedance j0.8 ohm supplies a resistive load of 500 A at 300 V. The sending end power factor is: (ISRO (VSSC) Technical Assistant Electrical 2017)
A. Unity
B. 0.8 lagging
C. 0.8 leading
D. 0.6 lagging
Correct Answer: D
Solved Example: 9910-03
A transmission line having 50 $\Omega$ impedance is terminated in a load of (40 + j30) $\Omega$. The VSWR is: (TN TRB EC 2012)
A. 1.333
B. 0.8
C. 1
D. 2
Correct Answer: D
Solved Example: 9910-04
A 100 V peak signal at 1 GHz is applied to a transmission line of characteristic impedance 100 $\Omega$, terminated with an antenna of 75 $\Omega$. The peak values of reflected and incident currents are: (UPRVUNL AE EC 2016)
A. 0.142 A, 1 A
B. 0.284 A, 1 A
C. 0.142 A, 2 A
D. 1 A, 0.142 A
Correct Answer: A
Solved Example: 9910-05
If a transmission line is terminated with a resistance equal to its characteristic impedance: (URSC (ISRO) Tech Asst (Electronics): Mar 2019)
A. Reflection coefficient will be unity
B. Standing wave ratio will be minimum
C. The line loss will be maximum
D. The input impedance will be twice the terminating resistance
Correct Answer: B
Solved Example: 9910-06
A transmission line of surge impedance 300 Ω is connected to a load of 300 $\Omega$. The reflection coefficient of transmission line at the load end will be: (UPPCL AE EE Paper 1 Jan 2019 Shift I)
A. 0
B. -1
C. 2
D. +1
Correct Answer: A