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# Electromagnetic questions for GATE-2018

1) The dominant mode frequency  of a waveguide is  $f_c$ with air  separating the parallel plates of waveguide. By introducing the dielectric with ($\epsilon$ instead of air , the dominant frequency of the waveguide

a) Increases

b) Decreases

c) Remains same

d) Zero

2) Air filled waveguide has a dominant mode cut off frequency of 9 GHz. One of the dimensions of the waveguide is

a) 4.3 cm

b) 1.66 cm

c) 3.3 cm

d) 0.8 cm

3) A 50 ohm  characteristic impedance line is connected to load which has a reflection coefficient of 0.268. If vin=15v, net power delivered to load will be

a)0.139 W

b)1.39 W

c)0.278 W

d)2.78 W

4) A waveguide has a separation of 3 cm for the broader dimension and carries the dominant mode at an unknown frequency. If the wave impedance is 550 ohm, the unknown frequency f is

a) 7.66 GHz

b) 8.66  GHz

c) 6.66 GHz

d) 10.66 GHz