Antenna Parameters Questions and Answers – Antenna Noise Temperature

This set of Antennas Multiple Choice Questions & Answers (MCQs) focuses on “Antenna Noise Temperature”.

1. Relation between brightness temperature T_B and physical body temperatureT_p is ____
a) T_B=\((1-\mid\Gamma_s \mid^2) T_p\)
b) T_B=\(T_p/(1-\mid\Gamma_s \mid^2)\)
c) T_B=\((1-\mid\Gamma_s \mid)T_p\)
d) T_B=\((1-\mid\Gamma_s \mid)^2 T_p\)
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2. If the reflection co-efficient is ½ then emissivity is ___
a) 3/4
b) 1/4
c) 1/2
d) 3/2
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3. Overall receiver noise temperature expression if T₁, T₂… are amplifier 1, 2, and so on noise Temperature and G₁, G₂, and so on are their gain respectively is_____
a) T = \(T_1+\frac{T_2}{G_1}+\frac{T_3}{G_1 G_2}+⋯ \)
b) T = T₁+T₂ (1-G₁)+T₃(1-G₁G₂)+⋯
c) T = \(T_1+\frac{T_2}{(1-G_1)}+\frac{T_3}{(1-G_1 G_2)}+⋯\)
d) T = T₁+T₂ (G₁)+T₃(G₁G₂)+⋯
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4. Total noise power of the system is P=_____
a) k(T_A+T_R)B
b) k(T_A+T_R)/B
c) k(T_R)B
d) kB/T_sys
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5. What is the relation between noise temperature introduced by beam T_B and the antenna temperature T_A when the solid angle obtained by the noise source is greater than antenna solid angle?
a) T_A= T_B
b) T_A > T_B
c) T_A < T_B
d) T_A « T_B
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6. Which expression suits best when the solid angle obtained by the noise source is less than antenna solid angle?
a) P_A Ω_A=P_B Ω_B and ΔT_A=\(\frac{\Omega_B}{\Omega_A} T_B\)
b) P_A Ω_B=P_B Ω_A and ΔT_A=\(\frac{\Omega_B}{\Omega_A} T_B\)
c) ΔT_A=\(\frac{\Omega_A}{\Omega_B} T_B\) and P_A Ω_B=P_B Ω_A
d) ΔT_A=\(\frac{\Omega_A}{\Omega_B} T_B\) and P_A Ω_A=P_B Ω_B
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7. Expression for noise figure F related to the effective noise temperature T_e is ____
a) \(F=1+\frac{T_e}{T_o}\)
b) \(F=1+\frac{T_0}{T_e}\)
c) \(F=1-\frac{T_e}{T_o}\)
d) \(F=1-\frac{T_0}{T_e}\)
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8. Effective noise temperature T_e in terms of noise figure is ____
a) T_e=T_o (F-1)
b) T_e=T_o/(F-1)
c) T_e=T_o/(F+1)
d) T_e=T_o (F+1)
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9. Which of the following statement is false?
a) Noise power of antenna depends on the antenna temperature as well as the noise due to the receiver surroundings
b) Noise figure value lies between 0 and 1
c) Any object with physical temperature greater than 0K radiates energy
d) Noise power per unit bandwidth is kT_A W/Hz
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10. Find the effective noise temperature if noise figure is 3 at room temperature (290K)?
a) 290K
b) 580K
c) 289K
d) 195K
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11. What should be the noise figure value at which the effective noise temperature equals to room temperature?
a) 2
b) 1
c) 0
d) 1/T_(o )
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Sanfoundry Global Education & Learning Series – Antennas.

To practice all areas of Antennas, here is complete set of 1000+ Multiple Choice Questions and Answers.

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