CBSE NET COMPUTER SCIENCE FREE MOCK TEST 3This entry was posted in MOCK TEST SERIES on April 9, 2017 by nikhilarora 1. The postfix expression AB+CD–* can be evaluated using a stack tree queue linked list 2. Consider the following pseudo code segment : K:=0 for i1:= l to n for i2:= 1 to i1 : : : for im:= 1 to im–1 K:= K+1 The value of K after the execution of this code shall be C(n + m – 1, m) C(n – m + 1, m) C(n + m – 1, n) C(n – m + 1, n) 3. The post order traversal of a binary tree is DEBFCA. Find out the preorder traversal. ABFCDE ADBFEC ABDECF None of the above 4. Which command is the fastest among the following ? COPY TO COPY STRUCTURE TO COPY FILE COPY TO MFILE-DAT DELIMITED 5. Page Shift Keying (PSK) Method is used to modulate digital signal at 9600 bps using 16 level. Find the line signals and speed (i.e. modulation rate). 2400 bauds 1200 bauds 4800 bauds 9600 bauds Answer: A Explanation: s=n/r r= log2L = (log2)16 = 4 s= 9600/4=2400 bauds 6. The command that unix offers to a user to find out whether he can send messages to a particular terminal are finger and who finger –mesg and who –T finger –I and who –t finger –I and who –T 7. If the user has read a news item he cannot read it again because of creation of the file _news_time news.time news.time news_time 8. Which of the following is true related to ‘Satisfiable’ property? A statement is satisfiable if there is some interpretation for which it is false A statement is satisfiable if there is some interpretation for which it is true A statement is satisfiable if there is no interpretation for which it is true A statement is satisfiable if there is no interpretation for which it is false 9. Different learning methods does not include (a) Memorization (b) Analogy (c) Deduction (d) Introduction 10. What is Transposition rule? (a) From P → Q, infer ~Q → P (b) From P → Q, infer Q → ~P (c) From P → Q, infer Q → P (d) From P → Q, infer ~Q → ~P 11. The worst type of coupling is . (A) Data coupling. (B) control coupling. (C) stamp coupling. (D) content coupling 12. SRS is also known as specification of (A) White box testing (B) Stress testing (C) Integrated testing (D) Black box testing 13. Modifying the software to match changes in the ever changing environment is called (A) adaptive maintenance (B) corrective maintenance (C) perfective maintenance (D) preventive maintenance 14. Three dimensional computer graphics become effective In the late a. 1960 b. 1980 c. 1970 d. 1950 15. The brightness of each pixel is Compatible Incompatible Both a & b None of these 16. Given the language L-{ab, aa, baa}, which of the following strings are in L*? 1) abaabaaabaa 2) aaaabaaaa 3) baaaaabaaaab 4) baaaaabaa 1,2 and 3 2,3 and 4 1,2 and 4 1,3 and 4 17. Consider the following grammar. S ::= AB A ::= a A ::= BaB B ::= bbA Which of the following is false? No string produced by the grammar has four consecutive b s No string produced by the grammar has three consecutive a s No string produced by the grammar has an odd number of consecutive b s The length of every string produced by the grammar is even. 18. If every string of a language can be determined whether it is legal or illegal in finite time the language is called Decidable Undecidable Interpretive Non deterministic 19. Assume statements S1 and S2 defined as : S1 : L2-L1 is recursive enumerable where L1 and L2 are recursive and recursive enumerable respectively. S2 : The set of all Turing machines is countable. Which of the following is true ? S1 is correct and S2 is not correct. Both S1 and S2 are correct. Both S1 and S2 are not correct. S1 is not correct and S2 is correct. 20. TM is more powerful than FSM because a) the tape movement is confined to one direction b) it has no finite state control c) it has the capability to remember arbitrary long sequences of input symbols. d) none of the above 21. The language of all words(made up of a’s and b’s) with at least two a’s can be described by the regular expression a) (ab)*a and a(ba)* b) (a+b)* and (a*+b)* c) (a*+b)* and (a+b)* d) none of the above 22. Set of regular languages over a given alphabet set, is not closed under a) union b) complementation c) intersection d) none of the above 23. Set of regular languages over a given alphabet set, is not closed under a) has at least one b b) should end in an ‘a’ c) has no consecutive a’s or b’s d) has at least two a’s 24. What is the output of the following program? main ( ) { int x = 2, y = 5; if (x < y) return (x = x+y); else printf (“z1”); printf(“z2”); } (A) z2 (B) z1z2 (C) Compilation error (D) None of these 25. If x is one dimensional array, then pick up the correct answer (A) *(x + i) is same as &x[i] (B) *&x[i] is same as x + i (C) *(x + i) is same as x[i] +1 (D) *(x + i) is same as *x[i] Loading …