Radiation resistance of an antenna is 54 ? and loss resistance is 6 ?. If antenn

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Question
Radiation resistance of an antenna is 54 ? and loss resistance is 6 ?. If antenna has power gain of 10, then directivity is:
Options
A. 9
B. 11.11
C. data not sufficient
D. 10

Correct Answer

11.11

Explanation

Efficiency of antenna

Radiation resistance of an antenna is 54 ? and loss resistance is 6 ?. If antenna has power gain of

Power gain = 10

Thus directivity Radiation resistance of an antenna is 54 ? and loss resistance is 6 ?. If antenna has power gain of .

Exam Questions Papers problems

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1. A noiseless 3 KHz channel can transmit binary at the rate __________ .
Options
A. 12000 bps
B. 10000 bps
C. 6000 bps
D. 3000 bps

2. A rectangular waveguide, in dominant TE mode, has dimensions 10 cm x 15 cm. The cut off frequency is
Options
A. 10 GHz
B. 1 GHz
C. 15 GHz
D. 25 GHz

3. The analog signal given below is sampled at 1200 samples per second. m(t) = 2 sin 120 pt + 3 sin 240 pt + 4 sin 360 pt + 5 sin 480 pt + 6 sin 600 pt + 7 sin 720 pt. The folding (maximum) frequency is __________ .
Options
A. 300 Hz
B. 360 Hz
C. 600 Hz
D. 480 Hz

4. In a semiconductor material. The hole concentration is found to be 2 x 2.5 x 10¹⁵ cm^-3. If mobility of carriers is 0.13 m²/ v-s. Then find the current density if electric field intensity is 3.62 x 10^-19
Options
A. 7.6237 x 10^-4 A/cm²
B. 7.6237 x 10^-5 A/cm²
C. 7.6237 x 10^-3 A/cm²
D. none of these

5. A certain 8 bit uniform quantization PCM system can accommodate a signal ranging from - 1 V to + V. The rms value of the signal is V . The signal to quantization noise ratio is:
Options
A. 30 dB
B. 46.91 dB
C. 40 dB
D. 49.92 dB

6. Consider a unity feedback control system with open-loop transfer function The steady state error of the system due to a unity step input is :
Options
A. zero
B. K
C. 1/K
D. infinite

7. When phase-lag compensation is used in a system, then gain cross over frequency, bandwidth and undamped frequency are respectively
Options
A. Increased, Increased, Increased
B. Increased, Increased, Decreased
C. Increased, Decreased, Decreased
D. Decreased, Decreased, Decreased

8. What is the propagation constant for air filled wave guide with dimensions a = 1.59" and b = 0.795" at 4.95 GHz?
Options
A. 0.6698
B. 0.7698
C. 0.503
D. 0.6598

9. The equivalent form of the logical expression ABC + A BC + ABC + ABC + AB C is
Options
A. C + (A ? B)
B. (A + B + C)(A + B + C)
C. (A + B + C)(A + B + C)(A + B + C)
D. (A + B + C)(A + B + C)(A + B + C)

10. An air-filled rectangular waveguide has dimensions 8cm x 10cm . The phase velocity of guided wave at frequency of 3 GHz for TE₁₀ mode is
Options
A. 1.5 x 10⁸ m/s
B. 5.5 x 10⁸ m/s
C. 3.46 x 10⁸ m/s
D. 0.18 x 10⁷ m/s

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