DAMISETTY SRINIVASA NAIDU’SDBS INSTITUTE OF TECHNOLOGY

NH-5, Near Industrial Estate, DS Naidu Nagar, Kavali, SPSR Nellore (Dt)II MID EXAMINATIONS

Subject: EMTL Branch:II- IIsem ECEDuration: 90 mnts Max.Marks: 30

______________________________________________________________________________Answer any three questions:

1. a)Obtain wave equations for conducting medium

b) A 300MHz uniform plane wave propagates through fresh water for which µr, =1

εr =78. Find(i) attenuation constant (ii) phase constant (iii) wave length (iv) intrinsic impedance (v) wave velocity

2. a) Derive an expression for reflection coefficient of an EM wave when it is incident normally on a dielectric.b) Write short notes on the following (i) surface impedance (ii) Brewster angle (iii) Total internal reflection.(c) A parallel polarized wave propagates from air to a dielectric at Brewster angle of 750c, calculate εr of the dielectric

3. (a) Derive the expression for input impedance of a line when it is terminated into (i) Z0 (ii) short circuited (iii) open circuited (b) At 8MHz , the characteristic impedance of a transmission line is (40 –j2)Ω and the propagation constant is (0.01 +j0.18) per m. Find primary constants.(c) List out types of transmission lines with diagrams and explain the applications of diagrams and explain the applications of transmission lines.

4. (a) Explain the significance and utility of , and line

(b) Explain what is meant by voltage reflection co-efficient in a transmission line(c) A 75Ω line is terminated by a load of 120+j80 Ω, find the maximum and minimum impedance on the line.

5. (a) Write a short notes on (i) quarter wave line (ii)smith chart (iii) stub matching

(b) Calculate the reflection coefficient and VSWR for a 50 Ω line terminated with (i) Matched load (ii) short circuit (iii) +j50 Ω (iv) -j50 Ω . (c) Write the applications of smith chart.

DAMISETTY SRINIVASA NAIDU’S

DBS INSTITUTE OF TECHNOLOGY NH-5 Near Industrial Estate, DS Naidu Nagar, Kavali, SPSR Nell ore (Dt)

II . MID OBJECTIVE TYPE EXAMINATION

SUBJECT: EMTL BRANCH: ECE(II-IISem) Duration: 20min Max.Marks:10 Name of the student ______________________________________Roll No____________ Branch_________ Date___________Invigilator sign____________________ __________________________________________________________________________________ANSWER THE FOLLOWING ALL OBJECTIVE TYPE QUESTIONS:

1. For a plane wave E=3sin (2π107 t-0.4πx)ay v/m the wave length making use of the phase constant a) 36 b) 1 c) 6 d) 10 [ ]

2. = ____________ [ ]

a) η b)β c)α d)α +jβ

3. For good conductors which of the following is correct [ ]

a) b) c) d)

4. An em wave propagating through a material µr = 5, . The intresic impedance of the

material (η) is [ ]a)377Ω b266.39 Ω c)277.69 Ω d) 300Ω

5. The characteristic impedance of a free space is [ ]a)277Ω b)377 Ω c)120π Ω d) both b and c

6. Which of the following is correct relation for Zs [ ]a) Zs = Etan/Js b) Zs = Js/ Etan c) ) Zs = Js Etan d) Zs = Etan

7. Which of the following is the correct formula for Brewster’s angle [ ]

b)

8. In a god conductor E and H are [ ]a) In phase b) out of phase c) not related to each other d) differed by 450

9. The standing wave ratio for perfect transmission line is [ ]a)2 b)0 c) 1 d)-1

10. Condition for distortion less line is [ ](a) LG=RC b) LC=RG c) RL=CG d) None

11. For a distortion lineless line Zo= [ ]

a) b) c) d)

12. For a distortion less line the phase constant (β) [ ]

a) b) c) d)

13. Phase velocity (Vp) [ ]

a) (ω/β) b) c) d)

14. If f= 1KHz and β = 0.187 the Vp [ ]a) 3.46 x 103 km/sec b) 3.36 x 104 km/sec

c) 3.56 x 104 km/sec d)4.46 x 104 km/sec

15. Loading is the process of adding _______ [ ]a) capacitance b) resistance c) inductance d) conductance

16. A 50Ω transmission line is connected to a load impedance yielding a VSWR of unity. The load impedance is [ ]

a)50Ω b)100Ω c)1Ω d)0Ω

17. If maximum and minimum currents in a transmission line are 4A and 2 A respectively, CSWR isa)0.5 b)2 c)1 d)4 [ ]

18. The reflected voltage on a transmission line is zero the VSWR [ ]a)0.5 b)2 c)1 d)4

19. Which of the following works as impedance inverter [ ]

a) b)λ line c) d)

20. A transmission line having the parameters Z0 = 100Ω , ZR = 400Ω then reflection coefficient

a) 0.4 b)0.6 c) 0.8 d)1.0 [ ]