Theory of Automata and Formal Languages Unit 2 – Regular Expressions and Languages: AKTU previous year questions
28 AKTU questions from Unit 2 (Regular Expressions and Languages) asked in 2018–2025, tagged by marks, year and topic. In short: about 31 marks of every paper come from this unit; the most asked topic is Regular Expressions (7 times); 18 questions came back in a later year. The latest ones are listed below; on the page you can filter them by 2-mark or long questions, topic and repeats.
Unit 2 previous year questions
- Write the regular expression for the language containing strings over {0,1} ending with 01. (2 marks, 2025, Regular Expressions)
- Prove using Arden's Theorem the regular expression for the following transition diagram: States: A (start), B (final). Transitions: A --a--> A, A --b--> B, B --a--> B (7 marks, 2025, Arden's Theorem)
- Using Pumping Lemma, show that the language L = {aⁿbⁿcⁿ | n ≥ 0} is not regular. (7 marks, 2025, Pumping Lemma for Regular Languages)
- Prove that (a+b)*a(a+b)* is a regular language using Arden's Theorem. (7 marks, 2025, Arden's Theorem)
- Give regular expressions that represent the language (L), which has all binary strings having two consecutive 0s and two consecutive 1s over the alphabet Σ = {0, 1}. (2 marks, 2024, Regular Expressions)
- Compute the regular expression using Arden's Theorem for the following DFA. (7 marks, 2024, Arden's Theorem)
- State Pumping Lemma for Regular Language. Show that the given language L={ap | Where p is a prime} is not regular. (7 marks, 2024, Pumping Lemma for Regular Languages)
- Discuss closure properties (i.e. union, concatenation, complement, intersection and difference) of regular language. (7 marks, 2024, Closure Properties of Regular Languages)
- State Arden's Theorem. (2 marks, 2023, Arden's Theorem)
- State Kleen's Theorem. (2 marks, 2023, Regular Expressions)
- Determine the FA accepted by the language described by the regular expression: (0+1)*0(0+1)*0(0+1)* over the alphabet {0,1} and also mention the accepted language? (10 marks, 2023, Regular Expressions)
- Find the regular expression corresponding to the finite automata given below: (10 marks, 2023, Arden's Theorem)
Most asked Unit 2 topics
- Regular Expressions – asked 7 times
- Arden's Theorem – asked 7 times
- Pumping Lemma for Regular Languages – asked 7 times
Unit 2 question pattern
- 2-mark questions: 7 asked in 2018–2025
- 7-mark questions: 12 asked in 2018–2025
- 10-mark questions: 9 asked in 2018–2025
- About 31 marks from Unit 2 in every paper
- 18 questions were asked again in a later year
Unit 2 questions year by year
- 2025: 4 Unit 2 questions asked (23 marks across that year's papers)
- 2024: 4 Unit 2 questions asked (23 marks across that year's papers)
- 2023: 6 Unit 2 questions asked (44 marks across that year's papers)
- 2022: 6 Unit 2 questions asked (52 marks across that year's papers)
- 2019: 4 Unit 2 questions asked (23 marks across that year's papers)
- 2018: 4 Unit 2 questions asked (23 marks across that year's papers)