Explore topic-wise MCQs in Engineering.

A parallel polarized wave is incident from air into paraffin having relative permittivity 3, the value of its Brewster angle is

For a 400 kHz transmission line having L = 0.5 mH/km, C = 0.08 mF and negligible R and G, the value of propagation constant P will be

The Depth of penetration of EM wave in medium having conductivity at a frequency of 1 MHz is 25 cm. The depth of penetration at a frequency of 4 MHz will be

The radiation resistance of a /16 wire dipole in free space will be nearly

Two identical antennas are placed in the = p/2 plane as shown in the figure. The elements have equal amplitude excitation with 180 polarity difference, operating of the far-zone resultant electric field strength normalized with that of a single element, both computed for = 0, is

Calculate wave impedance for TE mode

In a 100 turn coil, if the flux through each turn is (t³ - 2t)mW_b, the magnitude of the induced emf in the coil at a time of 4 sec is

Consider a loss less antenna with a directive gain of + 6 dB. If 1 mW of power is fed to it the total power radiated by the antenna will be

The electric field of the incident wave is , where = 3 x 10⁹p and = 10 p. The electric field of the transmitted wave E_t is given by

Which of the following should dominant wave have?

A (75 - j 40) W load is connected to a co-axial line of z₀ = 75 at 6 MHz. The load matching on the line can be accomplished by connecting

A plane wave is characterized by the wave is

A plane electromagnetic wave travels in dielectric medium of relative permittivity 9. Relative to free space, the velocity of propagation in the dielectric is

Consider a 300 Ω, quarter wave long at 1 GHz transmission line as shown in figure. It is connected to a 10 V, 50 Ω source at one end is left open circuited at the other end. The magnitude of the voltage at the open circuit end of the line is

A hollow rectangular waveguide has dimensions a = 2b. Calculate the amount of attenuation, if the frequency is 3 GHz, and b = 1 cm.

The phase angle corresponding to /4 in a standing-wave pattern is

Calculate the directivity of an antenna for _E = 30 , _H = 60

Ferrite have

In a p type material the Fermi level is 0.3 eV above valence band. The concentration of acceptor atoms is increased. The new position of Fermi level is likely to be

In an n-p-n transistor, the majority carriers in the base are

The amount of photoelectric emission current depends on

Assertion (A): A p-n junction has high resistance in reverse direction.

Reason (R): When a reverse bias is applied to p-n junction, the width of depletion layer increases.

In the circuit of figure the function of resistor R and diode D are

As compared to an ordinary semiconductor diode, a Schottky diode

In a bipolar transistor which current is largest

The v-i characteristics of a FET is shown in figure. In which region is the device biased for small signal amplification

Crossover distortion behaviour is characteristic of

If a_ac for transistor is 0.98 then _ac is equal to

Assertion (A): The conductivity of p type semiconductor is higher than that of intrinsic semiconductor.

Reason (R): The addition of donor impurity creates additional energy levels below conduction band.

In an n-p-n transistor biased for operation in forward active region

An increase in temperature increases the width of depletion layer.

In a 4 bit weighted resistor D/A converter, the resistor value corresponding to LSB is 32 k . The resistor value corresponding to MSB will be

Consider a unity feedback control system with open-loop transfer function The steady state error of the system due to a unity step input is :

If x[n] then the sequence x[n] is

The impulse response and the excitation function of a linear time invariant causal system are shown in figure (a) and (b) respectively. The output of the system at t = 2 sec is equal to

Consider a stable and causal system with impulse response h(t) and system function H(S). Suppose H(S) is rational, contains a pole at S = - 2, and does not have a zero at the origin. The location of all other poles and zero is unknown for each of the following statements. Let us determine whether statement is true or false.

1. f[h(t) e^-3t] converges
2. 
3. h(t) has finite duration
4. H(s) = H(- s)

At room temperature the current in an intrinsic semiconductor is due to

Work function is the maximum energy required by the fastest electron at 0 K to escape from the metal surface.

The most commonly used semiconductor material is

In which of these is reverse recovery time nearly zero?

A transistor has a current gain of 0.99 in the CB mode. Its current gain in the CC mode is

In the following non planar graph number of independent loop equations are

A transmission line has a characteristic impedance of 50 and a resistance of 0.1 /m, if the line is distortion less, the attenuation constant (in Np/m) is

A certain 8 bit uniform quantization PCM system can accommodate a signal ranging from - 1 V to + V. The rms value of the signal is V . The signal to quantization noise ratio is:

In an ac circuit the fundamental component of current wave lags the corresponding voltage wave by 20 . The third harmonic component of current wave lags the corresponding voltage by an angle.

The output of a diode detector contains

Noise generated in a resistor is also known as

Which of the following is used to provide tracking between RF amplifier and local oscillator stages of receiver?

For global communication, the number of satellites needed is

In a radio receiver, if the intermediate frequency is too low