ISRO CS 2015 ISRO CS 2015 Please wait while the activity loads. If this activity does not load, try refreshing your browser. Also, this page requires javascript. Please visit using a browser with javascript enabled. If loading fails, click here to try again Question 1Which of the given number has its IEEE-754 32 bit floating point representation as 0 10000000 110 0000 0000 0000 0000 00002.53.03.54.5ISRO CS 2015 Digital Logic & Number representation Number Representation Discuss itQuestion 1-Explanation: IEEE-754 32 bit floating point representation has excess-128 notation and first MSB represents sign bit for mantissa, next 8 bits represents the exponent(excess 127) and last 23 bits represent the value of mantissa. Given, floating point = 0 10000000 110 0000 0000 0000 0000 0000 0 at MSB represents that mantissa is positive. Next 8 bits, i.e. 10000000 = exponent = 2128 but as it is excess 127 notation, so actual value of exponent = 2128 - 127 = 21 Value of mantissa in normalized form = 1.110 0000 0000 0000 0000 0000 Answer = (1.11)2 * 2 = 3.5 Option (C) is correct. Question 2The range of integers that can be represented by an n bit 2’s complement number system is:- 2n - 1 to 2n - 1 - 1- (2n - 1 - 1) to (2n - 1 - 1) - 2n - 1 to 2n - 1- (2n - 1 + 1) to (2n - 1 - 1) ISRO CS 2015 Digital Logic & Number representation Number Representation Discuss itQuestion 2-Explanation: In 2\'s complement numbers, the range of integers are from -2n-1 to 2n-1 - 1 Option (A) is correct.Question 3How many 32K X 1 RAM chips are needed to provide a memory capacity of 256K-bytes?83264128ISRO CS 2015 Computer Organization and Architecture CPU control design and Interfaces Discuss itQuestion 3-Explanation: Number of chips required = (256 K x 8) / (32 K x 1) = 64 Option (C) is correct.Question 4 A modulus -12 ring counter requires a minimum of 10 flip-flops 12 flip-flops 8 flip-flops 6 flip-flops ISRO CS 2015 Digital Logic & Number representation Sequential circuits Discuss itQuestion 4-Explanation: A ring counter requires \'n\' flipflops for \'n\' number of states. A modulus-12 counter has 12 states starting from 0000 to 1011, atleast 12 bits are required to design a modulus-12 counter. Question 5The complement of the Boolean expression AB ( B'C + AC ) is ( A\' + B\' ) + ( B + C\' )( A\' + C\' )( A\' + B\' ) + ( BC\' + A\'C\' )( A\' + B\' )( B + C\') + ( A + C\' )( A + B )( B\' + C )( A + C )ISRO CS 2015 Digital Logic & Number representation Logic functions and Minimization Discuss itQuestion 5-Explanation: Applying DeMorgan\'s law and after complementing: ( AB ( B\'C + AC ))\' = (A + B)\' + (B\'C + AC)\' = (A\' + B\') + ( B\'C)\' (AC)\' = (A\' + B\') + ( B + C\')(A\' + C\') Option (A) is correct.Question 6The code which uses 7 bits to represent a character isASCIIBCDEBCDICGrayISRO CS 2015 Number Representation Discuss itQuestion 6-Explanation: Basic ASCII encodes 128 specified characters and thus use 7 bits to represent each of these characters whereas Extended ASCII needs 8-bit for each character representation as it has a total set of 256 characters. Extended Binary Coded Decimal Interchange Code (EBCDIC) is an 8-bit binary code for numeric and alphanumeric characters. BCD encoding uses 4 bits to represent each digit from the range 0 to 9 in its binary form. In case of Gray codes, any number of bits can be used to represent a character, according to the requirement. So, Option (A) is correct.Question 7If half adders and full adders are implemented using gates, then for the addition of two 17 bit numbers (using minimum gates) the number of half adders and full adders required will be0, 1716, 11, 168, 8ISRO CS 2015 Digital Logic & Number representation Combinational Circuits Discuss itQuestion 7-Explanation: A Half Adder is used to add 2 single-bit binary numbers and a Full Adder is used to add 3 one-bit binary numbers which include two sum bits and one carry bit. To add two 17 bit numbers using minimum gates, the least significant bits of both the numbers can be added using a half adder and for remaining 16 bits of both the numbers, full adders can be used. 1 Half Adder and 16 Full Adders will be required. So, option (C) is correct.Question 8Minimum number of multiplexers required to realize the following function,f = A'B'C + A'B'C' Assume that inputs are available only in true form and Boolean constant 1 and 0 are available.1237ISRO CS 2015 Digital Logic & Number representation Combinational Circuits Discuss itQuestion 8-Explanation: The function can be simplified: f = A\'B\'(C+C\') = A\'B\' Since, we have to take the inputs in their true form(i.e, there is no way to get A\' or B\' directly), TWO Multiplexers will be required. 1st MUX will be used to get the function: AB 2nd MUX will be used to complement the output from the first, i.e, get A\'B\' NOTE:There are other ways to solve this too. Mux1: I0 = 0 I1 = A S = B Output = 0 + AB = AB Mux2: I0 = 1 I1 = 0 S = AB (output from Mux1) Output = (AB)\' = A\'B\' (which is the desired output)Question 9The number of 1's in the binary representation of (3*4096 + 15*256 + 5*16 + 3) are:891012ISRO CS 2015 Digital Logic & Number representation Number Representation Discuss itQuestion 9-Explanation: Given expression = 3*4096 + 15*256 + 5*16 + 3 = (2 + 1)*4096 + (8 + 4 + 2 + 1)*256 + (4 + 1)*16 + 2 + 1 = (2 + 1)*212 + (23 + 22 + 2 + 1 )*28 + (22 + 1)*24 + 2 + 1 = (213 + 212) + (211 + 210 + 29 + 28) + (26 + 24) + 2 + 1 As 213 is 1 followed by 12 zeros, 212 is 1 followed by 11 zeros and so on, adding all these numbers give total 10 one\'s So, option (C) is correct.Question 10The boolean expression AB + AB'+ A'C + AC is independent of the boolean variableABCNone of theseISRO CS 2015 Digital Logic & Number representation Logic functions and Minimization Discuss itQuestion 10-Explanation: AB + AB\' + A\'C + AC = A(B + B\') + C(A + A\') = A + C(/pre) As the expression is independent of \'B\', option (B) is correct. 12345678 There are 80 questions to complete. You have completed questions question Your accuracy is Correct Wrong Partial-Credit You have not finished your quiz. If you leave this page, your progress will be lost. Correct Answer You Selected Not Attempted Final Score on Quiz Attempted Questions Correct Attempted Questions Wrong Questions Not Attempted Total Questions on Quiz Question Details Results Date Score Hint Time allowed minutes seconds Time used Answer Choice(s) Selected Question Text All doneNeed more practice!Keep trying!Not bad!Good work!Perfect! Last Updated : 07 Sep, 2020 Share your thoughts in the comments Add Your Comment Please Login to comment...