০৫। A λ/8 section of transmission line is determined of load impedance of (2 - j 5) Ω. If characteristic impedance of line is 10 Ω. Then input impedance of line is
ক) 10 Ω
খ) (6.9 + j 7.24) Ω
গ) (1.75 + j 3.098) Ω
ঘ) (2 - j 5) Ω
০৬। A (0.75 - j50) ohm load is connected to a coaxial transmission line of Z0 = 75 ohms at a frequency of 10 GHz Which of the following will be the best method of matching?
ক) Connecting an inductance at the end
খ) Connecting a short circuited stub at the load
গ) Connecting a capacitance at some distance from the load
ঘ) Connecting a short circuited stub at some specified distance from the load
০৭। A (75 - j 40) W load is connected to a co-axial line of z0 = 75ω at 6 MHz. The load matching on the line can be accomplished by connecting
ক) a short circuit stub at the load
খ) an inductance at the load
গ) a short circuit stub at a specific distance from the load
ঘ) a capacitance at a specific distance from the load
০৮। A 10 GHz signal propagates in a waveguide with a phase velocity of 4 x 108 m/s. If the signal produces standing wave in the guide, then the distance between successive minimal will be
ক) 10 mm
খ) 20 mm
গ) 30 mm
ঘ) 40 mm
০৯। A 50 p characteristic impedance line is connected to a load which shows a reflection coefficients of 0.268. If Vin = 15 volt, then the net power delivered to the load will be
ক) 0.139 W
খ) 1.39 W
গ) 0.278 W
ঘ) 2.78 W
১০। A broadside array consisting of 200 cm wavelength with 10 half-wave dipole spacing 10 cm. And if each array element feeding with 1 amp. current and operating at same frequency then find the half power beamwidth
ক) 4°
খ) 2°
গ) 10°
ঘ) 15°
১১। A broadside array consisting of 200 cm wavelength with 10 half-wave dipole spacing 10 cm. And if each array element feeding with 1 amp. current and operating at same frequency then find the radiated power
ক) 730 W
খ) 73 W
গ) 100 W
ঘ) None
১২। A broadside array is shown in figure in which the elements are placed at equal distances. The direction of maximum radiation is represented by
ক) AA
খ) BB
গ) CC
ঘ) DD
১৩। A broadside array operating at 100 cm wavelength consist of 4 half-wave dipoles spaced 50 cm apart. Each element carries radio frequency current in the same phase and of magnitude 0.5 A. The radiated power will be
ক) 196 W
খ) 73 W
গ) 36.5 W
ঘ) 18.25 W
১৪। A circular waveguide carries TE11 mode whose radial electric-field is given by Er = E 0J1 (r) sin φ V/m where 'r' is the radial distance in cm, from the waveguide axis. The cut-off wavelength of the mode is
ক) 10 cm
খ) 3p cm
গ) 2p cm
ঘ) 8 cm
১৫। A conductor is said to be perfect if it has __________ conductivity
ক) finite
খ) infinite
গ) unity
ঘ) zero
১৬। A dipole antenna of λ/8 length has an equivalent total loss resistance of 1.5 Ω. The efficiency of the antenna is
ক) 0.89159%
খ) 8.9159%
গ) 89.159%
ঘ) 891.59%
১৭। A dipole antenna was radiating with some excitation in free space radiating a certain amount of the power. If this antenna is immersed in a lake where water is non-dissipative but has a dielectric constant of 81, the radiated power with the same excitation will
ক) decrease to finite non-zero value
খ) remain the same
গ) increase
ঘ) decrease to zero
১৮। A dominant wave is characterised by which of the following?
= 0 is frequently known as
can be