# Given = Em sin (ωt –βz). ?y in free space, thenwill be given as

1.

2.

3.

4.  None of the above

4 Explanation :
No Explanation available for this question

# In a homogeneous nonconducting region where μr = 1, the value of εr will be if given = 30π

1.  16

2.  8

3.  4

4.  32

4

16

Explanation :
No Explanation available for this question

# For a lossy transmission line short-circuited at the receiving end, the input impedance is given by (Z0 is the characteristic impedance, y is the propagation constant and I is the length of the line).

1.  Z0 coth y/

2.   Z0 cot y/

3.  Z0 tanth y/

4.  Z0 tan y/

4

Z0 tanth y/

Explanation :
No Explanation available for this question

# For a n- channel JFET in active region

1.  The gate voltage VGS increase the cross section for conduction

2.  The drain voltage VDD is negative w.r.t source

3.  the current in the n channel is due to electrons

4.  Increasing the reverse bias Vcs increase the cross section for conduction

4

Increasing the reverse bias Vcs increase the cross section for conduction

Explanation :
No Explanation available for this question

# If the pith off voltage of JFET=5V, then the cut off region is

1.  (5.0)1/2V

2.  5.0V

3.  2.5V

4.  (5.0)2/3V

4

5.0V

Explanation :
No Explanation available for this question

# A plane electromagnetic wave travelling along +z-direction, has its electric field given by Ex = 2 cos(t) and Ey = 2cos(t+90) the wave is

1.  linearly polarized

2.  right circularly polarised

3.  left circularly polarised

4.  elliptically polarised

4

left circularly polarised

Explanation :
No Explanation available for this question

# short grounded vertical antenna has a length L which is 0.05 λ at frequency f. If its radiation resistance at f is r ohms, then its radiation resistance at a frequency 2f will be

1.  R/2 ohms

2.  R ohms

3.  2R ohms

4.   4R ohms

4

4R ohms

Explanation :
No Explanation available for this question

# For a dipole antenna

1.  the radiation intensity is maximum along the normal to the dipole axis

2.  the current distribution along its length is uniform irrespective of the length

3.  the effective length equals its physical length

4.  the input impedance is independent of the location of the feed-point.

4

the radiation intensity is maximum along the normal to the dipole axis

Explanation :
No Explanation available for this question

# Two isotropic radiators A and B are placed along the x-axis at the positions (-λ /8, 0) and (+λ /8, 0) respectively. The elements are fed by currents of equal amplitude with the phase of B leading that of A by 900. The array pattern will have maximum

1.  In the direction of the + x axis

2.  At an angle of 450 with respect to the + x axis

3.   In the direction of + Y axis

4.   In the direction –x axis

4

In the direction –x axis

Explanation :
No Explanation available for this question

# A periodic function f(t0 of period T shown in the figure has Fourier series expansion of At t = T/4, the above series will converge to

1.  +V

2.  –V

3.   O

4.   None of these

4