Practice Test: Electronics Engineering (ECE)- 5 - Electronics and Communication Engineering (ECE)

Improve the sentence with suitable options by replacing the underlined word.

 He "lay" on the grass enjoying the sunshine.

Fill in the blanks :

 At times, we are all ______ to be mistaken.

There are two solutions of wine and water, the concentration of wine being 0.4 and 0.6 respectively. If five liters of the first solution be mixed with fifteen liters of the second, find the concentration of wine in the resultant solution.

Rajiv bought some apples at the rate of 25 for Rs. 400 and an equal number at the rate of 30 for Rs. 270. He then sold all at the rate of 10 for Rs. 180. Find his profit/loss percentage

Out of 10 persons working on a project, 4 are graduates. If 3 are selected, what is the probability that there is alteast one graduate among them ?

2 men and 3 boys can do a piece of work in 10 days, while 3 men and 2 boys can do the same work in 8 days. In how many days can 2 men and 1 boy do the work ?

In an exam, 60% of the candidates passed in Maths and 70% candidates passed in English and 10% of the candidates failed in both the subjects, 300 candidates passed in both the subjects. Find the total number of candidates appeared in the exam, if they took test in only two subjects that is Math and English.

In the figure, the value of resistor R is (I 5) ohms, where I is the current in amperes. The value of current I is

The velocity of propagation of electromagnetic wave in an underground cable with relative permittivity of 9 is

The function shown in the figure can be represented as

Consider an LTI system with impulse response h(t) = e^-5t u(t). Determine the output of the system for the input x(t) = 5 u(t)

The value of integral   is

A rectangular pulse x(t) is shown in the figure. Determine the value of  

If   and f(t) is     as t → ∞ . Determine the value of K

In the signal flow graph shown in the given figure, the value of C/R ratio is

What is the open-loop transfer function for an unity feedback system having root locus shown in the following figure ?

The digital circuit shown in the figure works as a  

The simplified form of Boolean function F(A,B,C) implemented by the given 3 × 8 decoder is

The contents of the accumulator in an 8085 microprocessor is altered after the execution of the instruction

Assuming that all the diodes are ideal in figure, the current in the diode D₂ is

Determine the upper and lower threshold voltage of the schmitt trigger shown below :

The transistor in the given circuit, should always be in saturation region. Take V_CE (sat) = 0V and V_BE = 0.7V. the minimum value of R_C is

A differential amplifier has input at non inverting terminal is 1050 μV and at inverting terminal 950 μV. What is the error in the differential output if CMRR is 1000.

Which one of the following type of negative feedback increases the input resistance and decreases the output resistance of an amplifier ?

The spectral density and auto correlation function of white noise are respectively.

For a random variable x having the probability density function is shown in the figure, what are the variance of random variable.

An amplitude modulated signal is given as, S(t) = 100 Cos 2pf_ct 50 Cos 2pf_mt.Cos 2pf_ct, where f_c  f_m. and f_c is the carrier frequency and f_m is the modulating signal frequency. The power efficiency is.

Signal x(t) = 4Sinc² 100t. Sin 500pt .At what sampling frequency should this signal be sampled to avoid aliasing ?

The value of   is

The solution of differential equation dy = (1-y) dx is

The rank of the matrix A is 2, when K is

Given    If C is a counter-clockwise path in the z-plane such that |z - i| = 1, the value of  is

In the circuit shown in figure, determine the maximum power absorbed by the load resistance R_L

In the circuit shown below, the switch is closed at t = 0. What is the initial value of the current through the capacitor C.

Determine the z-parameter for the network shown below.

At which frequency (in rad/sec) the thevenins equivalent impedance looking at terminals AB becomes purely resistive?

Consider  if  y(t) = Ae^-t  for    then value of A is

The 4-point DFT of sequence x[n] = [1,2,2,1] is

The output y(t) of a continuous-time system for the input x(t) is given by . Which one of the following is correct ?

For the NMOS and PMOS shown in the figure are matched and   = 1mA/V²  and V _n = -V _p = 1 V. Determine V₀

Determine the region of operation of BJT in the given circuit.

In the silicon BJT circuit shown below. Assume the emitter area of transistor Q₂ is two time of area of Q₁. The value of I_o { Let b of the transistors are very large}

Determine the current i_o in the given circuit.

Consider a bar of silicon in which a hole concentration profile describe by P(x) = P₀.e^-x/Lp. Find the current at x = 0, given P₀ = 10¹⁶/cm³, L_p = 1 mm and cross-sectional area of the bar is 100 mm² and D_p = 12 cm²/sec.

A system with the open loop transfer function   is connected in a negative feedback gain of unity. What is the value of K for which the system is unstable.

In the system shown below x(t) = e^-2t u(t). Determine the output y(t) in steady state.

The polar diagram of a conditionally stable system for open loop gain K = 1 is shown in the figure. The open loop transfer function of the system is known to be stable. The closed loop system is stable for 

The sensitivity of transfer function  with respect to the parameter K is -0.5, Determine the value of K

Given two binary FSK signals    i = 1, 2.The minimum frequency separation of these two signals such that they are orthogonal is

A block code is transmitted in NRZ invent-one-one format with voltage levels

            6V → ‘1’

            -6V → ‘0’

Three code words are sent : 10010, 11110, 01001. Over these three transmitted code words the average voltage is

A signal is given by,

            γ(t) = s(t) n(t)

            where s(t) = 20 Cos2π4000t 40 Cos2π2000t and the noise n(t) is white with power spectral density η₀ = 1 W/Hz. The total received signal is put through a band pass filter with pass band between 100 to 110 Hz. The value of SNR at the output of filter is

The base band signal m(t) is recovered from the DSB-Sc signal s(t) = m(t). Cos2πf_ct, by multiplying s(t) by the locally generated carrier Cos (2πf_ct φ). The product is passed through a LPF which rejects the double frequency signal. If the base band signal is band limited to 4KHz, what is the minimum value of f_c for which m(t) can be recovered by filtering ?

A plane wave in free space  is incident normally on a large block of material  . which occupies z > 0. If the incident electric field is = 10 Cos (ωt z)     V/m, the reflected magnetic field is :

A plane wave with    is incident normally on a thick plane conductor lying in the X-Y plane. Its conductivity is 6 × 10⁶ s/m and surface impedance is 5 × 10^-4

?.  The skin depth of conductor is

The volume of the paralleopipe whose sides are given by  is

A number in 4 bit 2 5 complement representation is 1101. This number when stored using 8-bits will beA number in 4 bit 2’5 complement representation is 1101. This number when stored using 8-bits will be

Four variable K-map is shown in the figure. The essential prime implicants are

An 8085 microprocessor is interfaced to a 8KB RAM as shown below. The address range of the RAM is

If z = x – iy and   = p iq, then     is

The Newton – Raphson method is used to find the roots of the equation f(x) = x - cosπx   If the initial guess for the root is 0.5, then the value of x after the first iteration is

The eign value of the matrix     are,

The value of     is