Boolean Algebra & Logic Circuits (Cambridge (CIE) A Level Computer Science): Exam Questions

Exam code: 9618

47 mins7 questions
1a3 marks

The truth table for a logic circuit is shown.

INPUT

OUTPUT

A

B

C

D

T

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1

Write the Boolean logic expression that corresponds to the given truth table as the sum-of-products.

1b2 marks

Complete the Karnaugh map (K-map) for the given truth table.

4x4 Karnaugh map with labels AB and CD; columns marked 00, 01, 11, 10, and rows marked 00, 01, 11, 10, with empty cells.
1c2 marks

Draw loop(s) around appropriate group(s) in the K-map to produce an optimal sum-of-products.

1d3 marks

(i) Write the Boolean logic expression from your answer to part (c) as the simplified sum-of-products.

(2)

(ii) Use Boolean algebra to write your answer to part (d)(i) in its simplest form.

(1)

2a3 marks

The truth table for a logic circuit is shown.

INPUT

OUTPUT

A

B

C

D

X

0

0

0

0

0

0

0

0

1

1

0

0

1

0

1

0

0

1

1

0

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1

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1

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0

Write the Boolean logic expression that corresponds to the given truth table as the sum‑of‑products.

2b2 marks

Complete the Karnaugh map (K‑map) for the given truth table.

2c2 marks

Draw loop(s) around appropriate group(s) in the K‑map to produce an optimal sum‑of‑products.

2d2 marks

Write the Boolean logic expression from your answer to part (c) as the simplified sum‑of‑products.

3a2 marks

The diagram shows a logic circuit.

Logic circuit diagram with inputs A, B, C. Includes AND, OR, NOT gates; Q, R, S outputs lead to Z. P denotes NOT gate output.

Write the Boolean expression that corresponds to the logic circuit as a sum-of-products.

3b5 marks

Complete the Karnaugh map (K-map) for the Boolean expression:

A with bar on top. B with bar on top. C with bar on top space plus stack space A with bar on top. B with bar on top. C space plus space A. B with bar on top. C with bar on top space plus space A. B with bar on top. C space plus space A. B. C with bar on top space plus space A. B. C

A blank 2x4 Karnaugh map with labels A, BC, rows 0, 1, and columns 00, 01, 11, 10, used for simplifying Boolean expressions.

(2)

(ii) Draw loop(s) around appropriate group(s) in the K-map to produce an optimal sum-of-products.

(2)

(iii) Write the Boolean expression from your answer to part (c)(ii) as a simplified sum-of-products.

(1)

4a2 marks

The diagram shows a logic circuit.

Logic circuit diagram showing inputs A, B, C through NOT gates, combining in AND, OR, and final OR gate, outputting to Z.

Write the Boolean expression that corresponds to the logic circuit as a sum-of-products.

4b5 marks

(i) Complete the Karnaugh map (K-map) for this Boolean expression:

A with bar on top. B with bar on top. C with bar on top space plus space A with bar on top. B. C with bar on top plus space A with bar on top. B. C space plus space A. B with bar on top. C with bar on top – space space plus space A. B. C with bar on top plus space A. B. C

A blank Karnaugh map with two rows and four columns; labelled with variables A, B, and C. Column headers: 00, 01, 11, 10. Row headers: 0, 1.

(2)

(ii) Draw loop(s) around appropriate group(s) in the K-map to produce an optimal sum-of-products.

(2)

(iii) Write the Boolean expression from your answer to part c(ii) as a simplified sum-of-products.

(1)

5a3 marks

This diagram represents a logic circuit.

Logic circuit diagram with an AND gate taking inputs A, B, C, a NOT gate, another AND gate with input D, and an OR gate producing output Z.

Complete the truth table for the given logic circuit.

A

B

C

D

Working space

Z

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5b3 marks

Simplify the given Boolean expression using Boolean algebra.
Show your working.

Boolean equation with NOT A, AND B, AND C, AND D plus NOT A, AND B, AND C, AND NOT D plus NOT A, AND B, AND NOT C, AND D.
6a1 mark

This logic circuit represents the Boolean expression: X = stack straight A space plus space straight B space plus space straight C with bar on top

Logic gate diagram with three inputs labelled A, B, C, leading into a NOR gate, producing a single output labelled X.

Complete this truth table for the given logic circuit.

A

B

C

X

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6b1 mark

Apply De Morgan’s laws to the expression: X = stack straight A space plus space straight B space plus space straight C with bar on top

X = ...................................................................................

6c3 marks

Simplify the following expression using Boolean algebra.

Show all the stages in your simplification.

T = X.Y.Z + X.stack straight Y. with bar on topZ + straight X with bar on top

73 marks

This diagram represents a logic circuit.

Logic circuit diagram featuring a three-input NAND gate, a two-input AND gate, a two-input OR gate, and four inputs labelled A, B, C, D leading to output Z.

Simplify the given Boolean expression using Boolean algebra.
Show your working.

Y = straight A with bar on top. straight B with bar on top. straight C with bar on top. straight D with bar on top space plus space straight A with bar on top. straight B with bar on top. straight C. straight D with bar on top space plus space straight A with bar on top. straight B. straight C with bar on top. straight D with bar on top space plus space straight A with bar on top. straight B. straight C. straight D with bar on top