Electromagnetic Field Theory — Part 2 MCQs with Explanations

All of the above is the correct answer to “A square corner reflector is used in”. This question is standard in competitive examination syllabi for Electromagnetic Field Theory.

Path diversity and frequency diversity is the correct answer to “In microwave communication links, when fading due to rain attenuation occurs then technique adopted for solving the problem would include”. This question is standard in competitive examination syllabi for Electromagnetic Field Theory.

2.15 db is the correct answer to “The power gain of a half-wave dipole with respect to an isotropic radiator is”. This question is standard in competitive examination syllabi for Electromagnetic Field Theory.

True is the correct answer to “MUF is highest in periods of greatest sunspot activity.”. This question is standard in competitive examination syllabi for Electromagnetic Field Theory.

Very low is the correct answer to “The attenuation in waveguide above to cut off frequency”. This question is standard in competitive examination syllabi for Electromagnetic Field Theory.

An attenuator is the correct answer to “A waveguide operated below cut off frequency can be used as”. This question is standard in competitive examination syllabi for Electromagnetic Field Theory.

Larger wavelength than in the free space is the correct answer to “The wave in wave guide has”. This question is standard in competitive examination syllabi for Electromagnetic Field Theory.

Power radiated per unit solid angle in that direction is the correct answer to “Radiation intensity in a given direction is the”. This question is standard in competitive examination syllabi for Electromagnetic Field Theory.

A quarter wave line is the correct answer to “Which of the following impedance inversion is obtained”. This question is standard in competitive examination syllabi for Electromagnetic Field Theory.

No is the correct answer to “When a conductor moves in the field, so that it makes an angle 8 with the lines of flux, the force F is given as : F = Bl sin2 0.”. This question is standard in competitive examination syllabi for Electromagnetic Field Theory.

Large pulse is the correct answer to “High range resolution is obtained with”. This question is standard in competitive examination syllabi for Electromagnetic Field Theory.

infinite is the correct answer to “The input impedance of a short circuited lossless transmission line quarter wave long is”. This question is standard in competitive examination syllabi for Electromagnetic Field Theory.

200 Ω is the correct answer to “A loss-less line length x such that $$\beta {\text{x}} = \frac{\pi }{2}$$ is connected in between a line of characteristic impedance of 100 Ω and a load impedance of 400 Ω. The line so connected should have a characteristic impedance of”. This question is standard in competitive examination syllabi for Electromagnetic Field Theory.

Electric field is zero is the correct answer to “Inside a hollow conducting sphere”. This question is standard in competitive examination syllabi for Electromagnetic Field Theory.

27 MHz is the correct answer to “If the maximum electron density for E layer in ionosphere is 9 × 10 6 electrons/cm 3 , then its critical frequency is”. This question is standard in competitive examination syllabi for Electromagnetic Field Theory.

0 is the correct answer to “For a perfectly matched line the reflection coefficient has value of:”. This question is standard in competitive examination syllabi for Electromagnetic Field Theory.

Zero is the correct answer to “The electric field inside a metal is always . . . . . . . .”. This question is standard in competitive examination syllabi for Electromagnetic Field Theory.

a quarter-wave line is the correct answer to “Impedance inversion may be obtained with-”. This question is standard in competitive examination syllabi for Electromagnetic Field Theory.

-50 nC is the correct answer to “Three point charges, Q 1 = 30 nC, Q 2 = -150 nC, and Q 3 = 70 nC, are enclosed by surface S. What net flux crosses S”. This question is standard in competitive examination syllabi for Electromagnetic Field Theory.

0 is the correct answer to “A transmission line is terminated at its characteristic impedance The reflection coefficient is”. This question is standard in competitive examination syllabi for Electromagnetic Field Theory.

8 J is the correct answer to “Given the electric field $$E = 2x\hat i - 4y\hat j{\text{ V/m}}$$ find the work done in moving a point charge of 2 C from (2, 0, 0)m to (0, 0, 0)m.”. This question is standard in competitive examination syllabi for Electromagnetic Field Theory.

Locus [B] is the correct answer to “A transmission line of characteristic impedance 75 ohms is terminated with an impedance of 50 ohms. The line length is increased from zero. What will be the locus of the input impedance at the other end of the line? (N.B. : Reference impedance of Smith Chart = 50 Ohms)”. This question is standard in competitive examination syllabi for Electromagnetic Field Theory.

0 is the correct answer to “For the vectors \[\overline A = x{{\hat a}_x} + y{{\hat a}_y}\] and \[\overline B = z{{\hat a}_z},\,\nabla .\left( {\overline A \times \overline B } \right)\] is”. This question is standard in competitive examination syllabi for Electromagnetic Field Theory.

50 V is the correct answer to “A conductor of length 1 m moves at right angles to a uniform magnetic field of flux density 2 Wb/m 2 with a velocity of 50 m/s. What is the value of the induced e.m.f. when the conductor moves at an angle of 30° to the direction of the field”. This question is standard in competitive examination syllabi for Electromagnetic Field Theory.

2E is the correct answer to “The parallel-plate capacitor shown in the figure has movable plates. The capacitor is charged so that the energy stored in it is E when the plate separation is d. The capacitor is then isolated electrically and the plates are moved such that the plate separation becomes 2d. At this new plate separation what is the energy stored in the capacitor, neglecting fringing effects”. This question is standard in competitive examination syllabi for Electromagnetic Field Theory.

1, 2 and 3 only is the correct answer to “The solutions to many problems involving electric fields are simplified by making use of equipotential surfaces. An equipotential surface is a surface: 1. On which the potential is same everywhere 2. The movement of charge over such a surface would require no work 3. The tangential electric field is zero 4. The normal electric field is zero Which of the above statements are correct”. This question is standard in competitive examination syllabi for Electromagnetic Field Theory.

Zero is the correct answer to “Two identical coaxial coils carry the same current I but in opposite directions. The magnitude of the magnetic field B at a point on the axis midway between the coils is”. This question is standard in competitive examination syllabi for Electromagnetic Field Theory.

infinity is the correct answer to “Consider a transmission line of characteristic impedance 50 ohms and the line is terminated at one end by +j50 ohms, the VSWR produced in the transmission line will be”. This question is standard in competitive examination syllabi for Electromagnetic Field Theory.

2.0 is the correct answer to “If the maximum and minimum voltages on a transmission line are 4 V and 2 V respectively, for a typical load, VSWR is”. This question is standard in competitive examination syllabi for Electromagnetic Field Theory.

More likely to radiate is the correct answer to “When compared with stripline, the major disadvantage of microstrip line is”. This question is standard in competitive examination syllabi for Electromagnetic Field Theory.

15.9 µm is the correct answer to “Some unknown material has a conductivity 10 6 mho/m and a permeability of 4π × 10 -7 H/m. The skin depth for the material at 1 GHz is”. This question is standard in competitive examination syllabi for Electromagnetic Field Theory.

a-2, b-3, c-1, d-4 is the correct answer to “Match List-I with List-II and select the correct answer using the options given below: List-I (Load impedance) List-II (Value of Reflection Coefficient) a. Short circuit 1. 0 b. Open Circuit 2. -1 c. Line characteristic impedance 3. +1 d. 2 × line characteristic impedance 4. $$ + \frac{1}{3}$$”. This question is standard in competitive examination syllabi for Electromagnetic Field Theory.

both the coils is the correct answer to “The conducting thin coils X and Y (identical except for a thin cut in coil Y) are placed in a uniform magnetic field which is decreasing at a constant rate. If the plane of the coils is perpendicular to the field lines, which of the following statement is correct? As a result, emf is induced in:”. This question is standard in competitive examination syllabi for Electromagnetic Field Theory.

Faraday is the correct answer to “Who developed the concept of time varying electric field producing a magnetic field”. This question is standard in competitive examination syllabi for Electromagnetic Field Theory.

An accelerating charge is the correct answer to “Electromagnetic waves are produced by”. This question is standard in competitive examination syllabi for Electromagnetic Field Theory.

50 is the correct answer to “The characteristic impedance of a cable is about”. This question is standard in competitive examination syllabi for Electromagnetic Field Theory.

14 dB is the correct answer to “The VSWR of a microwave unit is 1.5, the return loss is:”. This question is standard in competitive examination syllabi for Electromagnetic Field Theory.

$$3{{\hat a}_x} + 3{{\hat a}_y} + 5{{\hat a}_z}$$ is the correct answer to “A medium is divided into regions I and II about x = 0 plane, as shown in the figure below. An electromagnetic wave with electric field $${\overrightarrow E _1} = 4{{\hat a}_x} + 3{{\hat a}_y} + 5{{\hat a}_z}$$ is incident normally on the interface from region-I. The electric field $${\overrightarrow E _2}$$ in region-II at the interface is”. This question is standard in competitive examination syllabi for Electromagnetic Field Theory.

balun is the correct answer to “To couple a co-axial line to a parallel line wire it is best to use”. This question is standard in competitive examination syllabi for Electromagnetic Field Theory.

1, 3 and 4 is the correct answer to “Consider the following statements regarding an electrostatic field: 1. It is irrotational 2. It is solenoidal 3. It is static only from a macroscopic view point 4. Work done in moving a charge in the field from one point to another is independent of the path of movement Which of these statements are correct”. This question is standard in competitive examination syllabi for Electromagnetic Field Theory.