# A glass fiber has refractive indices n1 of 1.5 and n2of 1.Assuming c=3.8x108m/s, the multi path time dispersion will be

1.  2.5ns/m

2.  2.5µs/m

3.  5 μs/m

4.  5 μs/m

4

5 μs/m

Explanation :
No Explanation available for this question

# A vertical wire of 1m length carries a current of 1A at 10MHz. The total radiated power is nearly

1.  0.43

2.  0.88

3.  7.3w

4.  73w

4

0.43

Explanation :
No Explanation available for this question

# A yagi antenna a driven antenna

1.  only

2.  with a reflector

3.  with one or more directors

4.  with a reflector and one or more directors

4

with a reflector and one or more directors

Explanation :
No Explanation available for this question

# A dipole antenna of λ/8 length has an equivalent total loss resistance of 1.5Ω.The efficiency of the antenna is

1.  0.89159%

2.  8.9159%

3.  89.15%

4.  891.59%

4

89.15\%

Explanation :
No Explanation available for this question

# Ratio of the activity of. end-fire antenna to that of a broad-side antenna is

1.  2

2.  3

3.  4

4.  5

4

4

Explanation :
No Explanation available for this question

# The radiation resistance of . antenna is 63Ω and loss resistance is 7Ω. If antenna has power gain of 16, then directivity is

1.  48.26 dB

2.  12.5 dB

3.  38.96 dB

4.  24.7 dB

4

12.5 dB

Explanation :
No Explanation available for this question

# For two identical antennas A and B spaced λ/4 apart as shown in the figure, it is possible to have null radiation along the array axis on the right side of B by having an excitation arrangement such that

1.  Phase of current in antenna B lags behind that of antenna A by π/2 radius

2.  currents in the antennas are in phase

3.  phase of current in antenna A lags behind that of antenna B by π/2 radians

4.  current in the antennas are out of phase by π radians

4

Phase of current in antenna B lags behind that of antenna A by π/2 radius

Explanation :
No Explanation available for this question

# The effective area of a transmitting antenna is one square metre, the effective area of the receiving antenna is 0.9 square metre and the wavelength is 0.03m. If distance between the transmitter and receiver is 100m and the power transmitted is 100w, then the power received will be

1.  1W

2.  10W

3.  30W

4.  40W

4

10W

Explanation :
No Explanation available for this question

# In order to radiate 100W from a circular loop 100W from a circular loop of circumference equal to 0.1λ, the current required will be

1.  10A

2.  100A

3.  200A

4.  400A

4

10A

Explanation :
No Explanation available for this question

# An antenna of input resistance 73 ohm is connected to a 50-ohm line. If losses are ignored then its efficiency will be nearly

1.  0.19

2.  0.81

3.  0.97

4.  1.19

4

0.97

Explanation :
No Explanation available for this question

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