# When electromagnetic waves are propagated in a waveguide

10 views
When electromagnetic waves are propagated in a waveguide

a) They travel along the walls of the waveguide b) They travel through the dielectric without touching the walls c) They are reflected from the walls but do not travel along the walls d) None of these

When electromagnetic waves are propagated in a waveguide They travel through the dielectric without touching the walls

## Related questions

What are the electromagnetic waves used in remote control?

What is the frequency range of VHF electromagnetic waves? A) 30-300 kHz B) 30-3000 kHz C) 30-300 MHz D) 30-3000 MHz

What are the dangers of electromagnetic waves?

In a circular waveguide the dominant mode is:  (1) TE01 (2) TE11 (3) TE20 (4) TE21

Which waves are demodulated by Costas loop? A) VSB B) SSB C) MSK D) DSBSC

A diode D, resistor R and inductor L and a switch S are connected in series.When a voltage V is applied across the circuit and switch is put on, the voltage across L changes as  A) V(1-exp(-t R/L)) B) Vexp(-t R/L) C) Ldi/dt +Ri D) V(1-t R/L)

A waveguide termination having VSWR of 1.1 is used to dissipate 100 watts of power. The reflected power will be A) 0.2268 W B) 0.5868 W C) 0.3468 W D) 0.4568 W

The EM wave which does not propagate through a rectangular waveguide with a=30 mm & b=15 mm is : a. EM wave of frequency 4.5 GHz b. EM wave of frequency 5.5 GHz c. EM wave of frequency 50 GHz d. EM wave of frequency 300 GHz

If frequency is decreased 4 times, then skin depth of an Electromagnetic wave inside a conductor will be :  A) halved B) quadrupled C) doubled D) no change

Two waves of the same frequency have opposite phase when the phase angle between them is?

Filters with the ___ characteristic are useful when a rapid roll-off is required because it provides a roll-off rate greater than –20/dB/decade/pole:  (1) Butterworth (2) Chebyshev (3) Bessel (4) Elliptical

The waveguide Magic Tee can be used as: a. An Isolator b. T/R switch in trans -receiver c. Adjustable Phase Shifter d. All of these

An antenna located in a city is a source of radio waves. How much time does it take the wave to reach a town 12,000 km away from the city?  a. 36 s b. 20 us c. 20 ms d. 40 ms

“In all cases of electromagnetic induction, an induced voltage will cause a current to flow in a closed circuit in such a direction that the magnetic field which is caused by that current will oppose the change that produces the current” is the original statement of

The threshold effect in demodulators is a) The rapid fall of output SNR when the input SNR falls below a particular value b) Exhibited by all the demodulators when the input SNR is low c) Exhibited by all AM suppressed carrier coherent demodulators d) Exhibited by correlation receivers

Ripple in output current of a step-down chopper feeding RLE load is maximum, when duty cycle is equal to:  (1) 1 (2) 0.5 (3) 0.75 (4) 0.33

In a 3-phase converter circuit during commutation when one SCR in one phase is turned on to turn-off an SCR in another phase, results in (A) voltage notching (B) harmonic distortion (C) voltage sag (D) voltage swell

In a JFET drain current is maximum when VGS is  (a) zero (b) negative (c) positive (d) equal to Vp

The emf induced in a coil is 1 volt when current in it changes from 0 to 100 mA in time 10mS. Its inductance (in mH) value is  A) 10 B) 50 C) 100 D) 1000

The current in a circuit with resistance in 6 amp. When an additional resistance of 4 ohms is inserted the current drops to 4 amp. The original resistance in ohms is

Three capacitors 15µf, 18µf and 12µf are connected in a circuit. Find equivalent capacitance when they are connected in – 1) Series 2) Parallel

In a three-phase system, when the loads are perfectly balanced, the value of neutral current is equal to: A. Zero B. One-third of the maximum value C. Two -third of the maximum value D. The maximum value

When two alternators A and B are operating in parallel, the increase in steam supply to alternator A will cause the active power output of (1) Alternator A to be decreased and alternator B to be increased (2) Alternators A and B is not affected (3) Alternators A and B is increased (4) Alternator A to be increased and alternator B to be decreased

In a lamp load when more than one lamp are switched on the total resistance of the load?

When the stator windings are connected in such a fashion that the number of poles are made half, the speed of the rotor of a synchronous motor?

The dominant mode in cylindrical waveguide

A rectangular waveguide is 5.1 cm by 2.4 cm (inside dimension). The cut off frequency of the dominant mode is

A rectangular waveguide is 4.2 cm by 1.85 cm. The cut-off frequency of the dominant mode through this waveguide is  (a) 3.57 GHz (b) 3.75 GHz (c) 3.70 MHz (d) 3.57 MHz

As per Shannon’s channel capacity theorem, if samples are transmitted in ‘T’ seconds over a noisy channel which is bandlimited to ‘B’ Hz. The number of samples ‘n’ is given by (symbols/notations carry their usual meaning) A) B/T B) T/B C) 2BT D) BT/2

In a microwave magic-T, E plane and H plane are  a) In phase b) Out of phase c) Isolated d) 90o out of phase

In VHDL all the statements written inside a process statement are  a. Concurrent b. Sequential  c. Both (a) and (b) d. None of the above

There resistors of 3Ω, 10Ω, and 15Ω are connected in parallel to a 30 V circuit the current that will flow through the 3Ω resistor is

What is the speed of an electromagnetic wave in water?

The transient current in lossless L-C circuit when excited from an AC source is, sine wave  (a) Critically damped (b) Underdamped (c) Overdamped (d) Undamped

The -------can conduct current in either direction and is turned-on when the breakover voltage is exceeded  A) SCR B) Diac  C) SCS D) Traic

When two synchronous machines are connected in parallel the synchronizing power tends to (A) accelerate the faster machine (B) retard the faster machine (C) retards the slower machine (D) pull the faster machine out of step

How will the total capacitance change, when two capacitors are connected in parallel?

When cells are arranged in parallel: