155. What is perculiar about a TEN mode propagating in a circular waveguide?
A. It has least attenuation and attenuation decreases with increase in frequency
B. It is the dominant mode
C. It is used for long microwave communication links
D. It has the largest attenuation

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156. The dominant mode in circular wavegu ides is
A. TEI
B. TM01
C. TE01
D. TMil

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157. The characteristic impedance of an air dielectric rectangular waveguide made from non-magnetic material mainly depends upon
A. the cut-off wavelength
B. the guide wavelength
C. the narrow and wide dimensions of the waveguide
D. the propagating mode

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158. If (?,0) is the free space wavelength, (A.c) is the cut of wavelength, then the guide wavelength (kg) is given by
A. X5 =X AD Z0
B. kg ? (xca 0)2
C. Z? (X/Xd2
D. none of these

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159. The number of half waves of electric intensity between two walls for a TE20 mode propagating in a waveguide is
A.2
B.1
C.4
D. indeterminate from given data

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160.  A 10 GHz wave is propagating in a waveguide having a wall separation of 4 cm. The largest number of half waves of electric intensity possible in this waveguide is
A.1
B.2
C.3
D. none of these

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161. One of the following statements is correct for dominant mode propagation in waveguide
A. The dominant moden needs the smallest waveguide to propagate for a given frequency
B.The dominant mode propagation is accompanied by higher losses
C. the dominant mode has the lowest cut-off wavelength
D. The dominant mode is the only mode used for wave propagation in a waveguide

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