Explore topic-wise InterviewSolutions in .

Correct ANSWER is (c) 100 dB

Best explanation: The default VALUE of R is 100dB. R is the amount by which the the Fourier TRANSFORM of the side-lobe magnitude should be below the main-lobe magnitude.

Right choice is (a) cheby2ord()

EXPLANATION: The cheby2ord() COMMAND is used to generate the order and the cut-off frequency of the type-2 CHEBYSHEV FILTER. Hence only cheby2ord() is correct.

The CORRECT option is (b) ONE of the many possible INTEGRALS

For EXPLANATION: Indefinite integrals can have many possible solutions. Only of the SOLUTION is provided by the int() function.

Right option is (B) False

To elaborate: We can do PROBLEMS pertaining to finding the area under a curve in MATLAB. This is because methods of definite and indefinite integration are PRESENT in the FORM of commands in MATLAB. This MAKES MATLAB so versatile.

Right choice is (c) int(t^2)

To EXPLAIN I would SAY: We can only integrate our voltage equation to get the current as a function of time. The syntax for int(t^2) is the correct syntax for the int() command. The REST is wrong since the int() command does not take string arguments.

The correct ANSWER is (c) DOUBLE

For explanation: The class of the result of QUAD command is double. This is an in-built command in MATLAB and it will give the answer in the format double.

The correct choice is (d) A CERTAIN ordered differential equation, within a range

Easiest EXPLANATION: MATLAB cannot FIND unnecessarily high ordered differential equation. It will compute a differential equation but the order of the differential equation is LIMITED.

Right ANSWER is (b) Radians

The EXPLANATION is: This is characteristic of MATLAB to TAKE input for angles and return angles in radians. Thus entering SIN(90) in MATLAB will not return 1, but entering sin(pi/2) will return 1.

The correct choice is (b) Using the clear all command

For explanation: The in-built command to CLOSE the windows containing graphs is ‘close all’. This command should be placed at the beginning of a function which creates graphs so that future commands do not AFFECT the GRAPH GENERATED every TIME the function is called.

The CORRECT option is (c) MULTIPLICATION in FREQUENCY (jw) domain

To elaborate: The fourier transform can be used to FIND the multiplication of two signals in time domain. The convolution of two signals in frequency domain is same as the multiplication of two signals in time domain.

The correct answer is (c) INPUT differentiating VARIABLE

The explanation is: The dsolve COMMAND returns a solution which is parameterized by the variable that has been used as a differential in the input FUNCTION. As such, there is no default variable for this command.

Correct choice is (d) INDEFINITE INTEGRATION

Explanation: The QUAD command is used to find the integral solution for LOW accuracy cases. It can only do definite integration. It cannot do any indefinite integration; for that, we NEED the int() command.

Right ANSWER is (b) Indefinite

Easiest explanation: If we introduce INFINITY as an argument to our command ‘quad()’, it will result in an error. This is because it will not take Inf as an input LIMIT. It can do definite integral over a FINITE range.

Correct option is (c) Superposition via Simulink

The best I can explain: We can MODEL our circuit in Simulink and then apply the superposition theorem to check if at all the circuit is following superposition theorem. To apply the theorem, find the I/V relationship across any branch due to a single SOURCE and switch of the rest of the sources. REPEAT this process for all the individual sources. Finally, turn on all the sources and check whether the I/V relationship is equal to the superposition of all the I/V sources previously calculated.

Right answer is (b) Cramer’s rule

Best explanation: It is EASIER to FIND the solution of a system of equations for a non-homogeneous system using Cramer’s rule. Now, the process is time consuming since we NEED to find higher order determinants for higher order SYSTEMS. This is why we go for Rouche’s theorem by hand. But MATLAB computes determinants very fast. Hence, without finding the rank, we can find the solution of a system of NONHOMOGENEOUS equations.

The correct option is (a) Consistency

Explanation: If the system of equations is not consistent, the student cannot EVER get a solution for the system of EQUATION. He has to check consistency by FINDING the rank of the matrix. Thereafter he can comment on the NATURE of SOLUTIONS the system possesses.

The CORRECT choice is (c) nzmax

Easy EXPLANATION: The nzmax is the command to find the MAXIMUM space allocated for SPARSE matrices. The maximum space is proportional to the number of non-zero ELEMENTS in the original matrix.

Right CHOICE is (b) False

To explain: The linspace commands generate numbers which are equidistant from each other and CONTAIN within a closed RANGE. Hence, they are not PSEUDORANDOM numbers and the statement is false.

Correct choice is (a) multiply it with the incoming signal

The BEST explanation: The rectangular window function is multiplied with the incoming signal so that the unrequired COMPONENTS can be filtered out from the signal. This is the BASIC principle of filtering.

Right OPTION is (a) Generate SMOOTHER phase plots

Easy EXPLANATION: The functioning of the unwrap command is based on the tolerance limit, ‘pi’, which is USED to multiply the input VECTOR with 2*pi so that it can return values for a smoother phase plot. Hence, Generate smoother phase plots is correct.

Right choice is (a) Left hand limit = right hand limit ≠ FUNCTION value

The BEST explanation: The condition of removal discontinuity is given by option Left hand limit = right hand limit ≠ function value only. Rest are incorrect because the two conditions of removal discontinuity is limn→n0 f(n) < ∞and f(n0) < ∞. So the function should have equal VALUES while reaching the limiting value from both directions and it should have a finite value at the limiting value. But since there is a discontinuity at the limiting value, the values after APPROACHING the function from both directions is not equal to the function value at the limiting value.

Correct answer is (d) quad(‘[F]’)

The explanation: The function, f, will be taken as a string input. Hence, we cannot use the int COMMAND since it takes SYMBOLIC arguments while the CLASS of our function is inline. Since the function is non-linear, we need to introduce it as a matrix to our quad() command. It takes string arguments so the correct answer should be quad(‘[]’).

The correct answer is (c) ei(x)

The best I can explain: The integration of the given function is stored in MATLAB as ei(x) or exponential integration of x. This YIELDS a solution of an exponentially increasing series. HENCE, EVEN though it BECOMES an infinite series, it will be represented as ei(x) whenever we COME across such an integration.

Correct option is (a) u-v rule

Explanation: If we give an ARGUMENT within our COMMAND DIFF() which is a product of multiple functions or division of two functions; we will get the result that will be generated according to the u-v rule. This MAKES MATLAB very versatile for the applications concerning differentiation.

The correct option is (a) True

To explain I would say: The PROCESS of Cramer’s rule will always YIELD a SOLUTION for the variables in a SYSTEM. But for a homogeneous system with no constant value, it will yield a 0 as a solution. HENCE all the variables will get a 0 as a solution, there-by yielding a trivial solution. This doesn’t imply that the system is inconsistent- this is why we go for comparing ranks, it will allow us to establish a more pertinent justification of the nature of the system.

Correct choice is (a) cheb1ord()

For explanation: The cheb1ord() COMMAND is inbuilt in MATLAB. It HELPS to generate the order of the type-1 CHEBYSHEV filter and ALSO it’s cut-off frequency.

Correct option is (d) Sometimes

To explain: Symbolic SUMMATIONS is available in MATLAB. This allows us to find SUM of series expansions. We can do infinite series SUMMATION in MATLAB. We can calculate the series to N terms and then MAKE n approaching infinity.

The correct option is (a) abs()

For explanation I would say: The abs() command is used to get the MODULUS of any complex number. The rest of the OPTIONS are wrong because they should be ‘atan2()’, ‘REAL()’ and ‘IMAG()’.

Correct CHOICE is (a) .25 megabytes

Explanation: The sparse MATRIX takes EXTREMELY small space from memory which is why it is so useful. The most plausible option amongst is .25 megabytes while the rest suggest PRETTY large amount of memory.

Right answer is (d) FIR filters using WINDOW METHOD

The explanation: The fir1() COMMAND is a pre-defined command in MATLAB and it uses the HAMMING Window method to obtain the Response of any FIR FILTER. Low Pass Filters FIR method would’ve been correct but FIR filters using Window Method is a more generalized answer.

Right option is (a) X

The best I can explain: Unless specified, the solve command would take x as the default variable who’s solution is being SOUGHT. If the FUNCTION did not have x as an independent PARAMETER, the default variable would’ve been variables NEAR to x.

Right option is (a) s

The best explanation: If no VARIABLE is specified within the laplace command, the function gives the laplace transform of the input function with ‘s’ as the INDEPENDENT variable. Hence, SIS CORRECT.

The correct ANSWER is (d) cumsum()

To explain: The correct syntax for the function which does CUMULATIVE summation is ‘cumsum()’. Hence option cumsum[] is wrong. The FUNCTIONS in options sumcum() and sumcum[] do not EXIST in MATLAB.

Right answer is (d) Depends on the DIFFERENTIAL equation

To EXPLAIN I would say: We can find the PARTICULAR integral for the differential equation ^dy⁄dx=5x by using int(5*x). We would need an ODE solver when the differential equation is LONG and has multiple ORDERS. Hence, it depends on the differential equation, how we want to select our command.

Correct answer is (a) quad(‘x.^2’,-2,3)

The best EXPLANATION: SINCE the FIRST limit provided to our quad command is a lower limit, we will get the answer same for the code quad(‘x.^2’,-2,3). We need to give the input function with the ‘ . ‘ operator since we are computing the value for EVERY instant and it is ADDING up.

The correct answer is (a) ODE solver

For explanation: The CASE for the CAPACITOR has an initial CONDITION. So the int() command won’t MERELY give the voltage, as a function of time, for the capacitor. We need to use the ode45 solver or the ode23 solver. The quad command won’t also give the TRUE solution for a voltage since it doesn’t return the complementary function.

The correct choice is (b) False

Best explanation: There are many differences between a difference EQUATION and a differential equation. But the most important would be that a difference equation TAKES FINITE steps of changes of our changing variable while a differential equation takes an infinitesimal change in our changing variable.

The correct ANSWER is (b) PARTICULAR Solution

The explanation: When we USE dsolve to find the solution of an ordinary differential equation, we get the general solution of the equation. Now, this equation comprises of both the complementary FUNCTION and the particular integral for the general solution. Hence, it is not that we only get the particular integral as a solution after using dsolve().

Right option is (d) Depends on the REPRESENTATION of the system

For explanation I would say: First we NEED to check if the system is represented by a set of equations or it is represented in terms of signals. If it is represented by a set of EQUATION, we need to GO for homogeneity first. If it is represented by the observation of input-output signals, we need to go by Superposition.

Right OPTION is (c) Determinant of co-efficient MATRIX is not equal to 0

To explain I would SAY: If the determinant of co-efficient matrix is 0, all the solutions will come to be Infinite. Thus, this is the condition to check before going for Cramer’s rule to check the SOLUTION of any system of EQUATIONS.

Right choice is (b) False

To elaborate: An expression is a combination of variables, OPERATORS and functions. It is not NECESSARY that only functions and variables are PRESENT in a mathematical expression. The statement ‘a=b+c’ contains no functions, but it only performs the ADDITION operation between b and c and assigns the value to a. The statement a=sum(b,c) shows no mathematical operation EXPLICITLY since the operation is done by the function itself.

The CORRECT option is (a) sparseid

The explanation is: The correct COMMAND to generate a sparse identity matrix is the SPEYE command. The issparse command checks whether an INPUT matrix is a sparse matrix. HENCE speye is correct.

Correct choice is (B) Normalized NORMAL Distribution

Best EXPLANATION: The Normalized normal distribution is used to generate random numbers random numbers using the randn command- this is the inbuilt working of the randn command. HENCE, Normalized Normal Distribution is correct.