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Edexcel GCSE Computer Science (1CP2) Exam Questions

Build a practice paper from 514 exam-style questions, each with its mark scheme and example answers. Print it, or answer it on paper and then open the mark schemes. Or browse the questions by topic.

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5 questions · 11 marks

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1Convert2 marksDenary to Binary Conversion Swap Remove

Computers manipulate binary patterns.

Convert the denary number 184 to 8-bit binary.

[2 marks]
Mark scheme

Award one mark for each correct nibble in the correct order:

  • 1011 (1)
  • 1000 (1)

0 marks if the response is not 8-bit binary.

Example answers and how they were marked
Full marks2/2

1011 1000

Why: 184 = 128 + 32 + 16 + 8: both nibbles are correct (2).

Some marks1/2

1011 1001

Why: Converts 185 instead (a slip in adding up the place values). The first nibble is correct (1); the second is not.

No marks0/2

0001 1101

Why: The bits are written in reverse, smallest place value first. Neither nibble is correct.

2Convert2 marksDenary to Negative Binary Conversion Swap Remove

Binary patterns can represent numbers.

Convert the 8-bit binary two's complement pattern 1111 1001 to denary.

[2 marks]
Mark scheme

Award one mark for each of:

  • − (negative sign) (1)
  • 7 (1)

The correct answer is −7

Example answers and how they were marked
Full marks2/2

−7

Why: The left-hand bit is worth −128: −128 + 121 = -7. Sign (1) and value (1).

Some marks1/2

7

Why: The value is right (1) but the minus sign is missing.

No marks0/2

249

Why: Reads it as an unsigned number, so neither the sign nor the value is right.

3Convert2 marksDenary to Negative Binary Conversion Swap Remove

Computer systems manipulate bit patterns.

Convert the 8-bit binary two's complement pattern 1000 0111 to denary.

[2 marks]
Mark scheme

Award one mark for each of:

  • − (negative sign) (1)
  • 121 (1)

The correct answer is −121

Example answers and how they were marked
Full marks2/2

−121

Why: The left-hand bit is worth −128: −128 + 7 = -121. Sign (1) and value (1).

Some marks1/2

121

Why: The value is right (1) but the minus sign is missing.

No marks0/2

135

Why: Reads it as an unsigned number, so neither the sign nor the value is right.

4Convert2 marksDenary to Negative Binary Conversion Swap Remove

Computer systems manipulate bit patterns.

Convert the 8-bit binary two's complement pattern 1100 1011 to denary.

[2 marks]
Mark scheme

Award one mark for each of:

  • − (negative sign) (1)
  • 53 (1)

The correct answer is −53

Example answers and how they were marked
Full marks2/2

−53

Why: The left-hand bit is worth −128: −128 + 75 = -53. Sign (1) and value (1).

Some marks1/2

53

Why: The value is right (1) but the minus sign is missing.

No marks0/2

203

Why: Reads it as an unsigned number, so neither the sign nor the value is right.

5Calculate3 marksAdding Binary Numbers Swap Remove

Computers manipulate binary patterns.

(a)

Complete the table to show the 8-bit result of the binary addition.

[2 marks]
1286432168421
10111001
10111100
Mark scheme

Award one mark for each correct nibble in the correct order:

  • 0111 (1)
  • 0101 (1)

0 marks if the response is not 8-bit binary.

Ignore a carry shown beyond the eighth bit.

Example answers and how they were marked
Full marks2/2

0111 0101

Why: 185 + 188 = 373, which needs 9 bits; the 8 bits that are kept are both correct (2).

Some marks1/2

0000 0101

Why: Forgets to carry the 1s. The second nibble is correct (1); the first is not.

No marks0/2

1011 1101

Why: Never carries. Neither nibble is correct.

(b)

State the name of the error that occurs when this addition is carried out.

[1 mark]
Mark scheme

Award one mark for:

  • overflow (error) (1)
Example answers and how they were marked
Full marks1/1

Overflow

Why: The result needs more bits than are available (1).

No marks0/1

Underflow

Why: A near miss: the result is too big for 8 bits, not too small.

No marks0/1

A syntax error

Why: A syntax error is a mistake in a program's code, not in arithmetic.

Questions by topic

2.1 Binary

Build a paper on this topic 58
Adding Binary Numbers 6 questions Binary and Hexadecimal Basics 10 questions Binary Shifts 6 questions Binary to Denary Conversion 6 questions Binary to Hexadecimal Conversion 6 questions Denary to Binary Conversion 6 questions Denary to Hexadecimal Conversion 6 questions Denary to Negative Binary Conversion 6 questions Hexadecimal to Binary Conversion 6 questions

2.2 Data representation

Build a paper on this topic 56
Character Sets 18 questions Images 19 questions Sound 19 questions

2.3 Data storage and compression

Build a paper on this topic 24
Compression 18 questions Units & Conversion 6 questions

3.1 Hardware

Build a paper on this topic 77
Embedded Systems 17 questions Fetch Decode Execute Cycle 15 questions Primary Memory 15 questions Secondary Memory 15 questions Stored Program Computers 15 questions

3.2 Software

Build a paper on this topic 124
File Management 18 questions Memory Management 16 questions Peripheral Management 11 questions Process Management 12 questions Purpose & Function of Operating Systems 17 questions Software Basics 13 questions User Management 18 questions Utility Software 19 questions

3.3 Programming languages

Build a paper on this topic 37
Low and High Level Languages 19 questions Translators 18 questions

4.1 Networks

Build a paper on this topic 138
Addressing 16 questions LANs & WANs 16 questions Network Speed 5 questions Packet Switching 16 questions Protocols & Layers 17 questions The Internet 16 questions Topologies 17 questions Wired Connections 17 questions Wireless Connections 18 questions

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