Boolean Logic Diagrams (OCR GCSE Computer Science)

Exam Questions

47 mins13 questions
1a2 marks

Complete the truth table in Fig. 1 for the Boolean statement P = NOT(A AND B).

A

B

P

0

0

1

0

1

1

0

1

1

0

Fig. 1

1b1 mark

Tick (✓) one box to identify the correct logic diagram for P = NOT(A AND B).

Three rows of logic gate diagrams with inputs A, B, and output P in a truth table. Column to tick the box if P equals NOT (A AND B).

Did this page help you?

24 marks

Complete the truth table for the following logic gate.

logic gate

A

B

Q

0

0

0

0

1

1

0

1

Did this page help you?

31 mark

State the number rows needed in a truth table for a Boolean expression with four inputs?

Did this page help you?

41 mark

What is the result of the Boolean expression A ∨ B when A = 0 and B = 1?

Did this page help you?

51 mark

Write the Boolean expression for a logic circuit with an AND gate followed by a NOT gate.

Did this page help you?

1a3 marks

A fast food restaurant offers half-price meals if the customer is a student or has a discount card.
The offer is not valid on Saturdays.

A computer system is used to identify whether the customer can have a half-price meal.

The table identifies the three inputs to the computer system:

Input

Value

A

Is a student

B

Has a discount card

C

The current day is Saturday

The logic system P = (A OR B) AND NOT C is used

Complete the following logic diagram for P = (A OR B) AND NOT C by drawing one logic gate in each box.

Bracket diagram with three entries labeled A, B, C competing to reach the final position labeled P. Entries A and B advance to the next round.
1b2 marks

A truth table can be produced for this logic circuit.

Describe the purpose of a truth table.

1c1 mark

State how many rows (excluding any headings) would be required in a truth table for the logic expression:

P = (A OR B) AND NOT C

Did this page help you?

2a3 marks

Draw the logic diagram for the logic system P = A OR (B AND C)

2b4 marks

Complete the truth table for the logic system P = NOT (A OR B)

A

B

P

0

0

1

0

1

1

0

Did this page help you?

3a2 marks

The logic diagram below (Fig. 2) shows a system made up of two connected logic gates.

Diagram of a NAND gate with two inputs labeled A and B, producing an output that is inverted by a NOT gate, leading to an output labeled Q.

Label the names of the two gates on the diagram above

3b4 marks

Complete the truth table below to show the output from the logic system in part(a).

A

B

C

0

0

0

1

1

0

1

1

Did this page help you?

42 marks

Draw the logic diagram represented by Q space equals space A space logical or space not B

Did this page help you?

15 marks

Draw the logic diagram represented by:

P =(A OR NOT B) AND (A OR C)

Did this page help you?

23 marks

Write the Boolean expression represented by the logic diagram below:

Logic circuit diagram featuring an AND gate with inputs A and B, an OR gate outputting P, and a NOT gate with input C. Lines connect gates to the OR gate.

Did this page help you?

35 marks

Complete the truth table for the Boolean expression:

P = (A AND B) AND  NOT C

A

B

C

P

0

0

0

0

0

0

1

0

0

1

0

0

0

1

1

0

1

0

0

Did this page help you?

43 marks

Given the logic circuit with inputs A, B, and C:

P = (A OR B) AND  NOT C

State the outputs when A = 1, B = 0, and C = 1.

Did this page help you?