Characteristic impedance of a transmission line is 50 ?. Input impedance of the

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Question
Characteristic impedance of a transmission line is 50 ?. Input impedance of the open circuited line.
Z_oc = 100 + J150 ?. When transmission line is short circuited, then value of the input impedance will be
Options
A. 50 ?
B. 100 + J150 ?
C. 7.69 + J11.54?
D. 7.69 - J11.54 ?

Correct Answer

7.69 - J11.54 ?

Explanation

Z_C = Z_OC - Z_SC ⟹ 50 = (100 + j150)(Z_SC) .

Electromagnetic Field Theory problems

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Options
A. (120p) ?
B. 377 ?
C. 226 ?
D. 629 ?

2. The torque (in mm) acting on a circular current loop of radius 1 mm in the xy plane, connected at the origin and with current 0.1 A, flowing in the sense of increasing in a magnetic field
is
Options
A.
B.
C. 10^-12p
D. - 10^-12p

3. Which of the following should dominant wave have?
Options
A. Lowest cut off frequency
B. Highest cut off frequency
C. No attenuation
D. No phase shift

4. A short circuited stub is shunt connected to a transmission line as shown in the figure is, if z₀ = 500 ohms, the admittance y seen at the function of the stub and the transmission line is
Options
A. (0.01 - j 0.02) mho
B. (0.02 - j 0.01) mho
C. (0.04 - j 0.02) mho
D. (0.02 + j 0) mho

5. Refractive index of glass is 1.5. Find the wavelength of a beam of light with a frequency of 10¹⁴ Hz in glass. Assume velocity of light is 3 x 10⁸ m/sec in vacuum.
Options
A. 4 ?m
B. 3 ?m
C. 2 ?m
D. 1 ?m

6. The input impedance of short-circuited line of length l where ?/4 < l < ?/2, is
Options
A. resistive
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7. Z_L = 200 ? and it is desired that Z_i = 50 ? The quarter wave transformer should have a characteristic impedance of
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A. 100 ?
B. 40 ?
C. 10000 ?
D. 4 ?

8. For F₁ layer the maximum ionic density is 2.3 x 10⁴ electrons per cc. The critical frequency for this layer will be
Options
A. 1.36 MHz
B. 13.6 MHz
C. 136 MHz
D. 1360 MHz

9. A wave is propagated in a waveguide at frequency of 9 GHz and separation is 2 cm between walls calculate the phase velocity for dominant mode.
Options
A. 3 x 10⁸ m/sec
B. 5 x 10⁸ m/sec
C. 1.5 x 10⁸ m/sec
D. 9 x 10⁸ m/sec

10. A plane wave is characterized by the wave is
Options
A. linearly polarized
B. circularly polarized
C. elliptically polarized
D. unpolarized

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