2021 CWSS Computing P1

COMMONWEALTH SECONDARY SCHOOL PRELIMINARY EXAMINATION 2021 COMPUTING Paper 1 (Theory) Name: ___________________________________ ( ) Class: ___________ SECONDARY FOUR EXPRESS / SECONDARY FIVE NORMAL (ACADEMIC) Monday 17 September 2021 7155/01 0800 – 1000 2 hours READ THESE INSTRUCTIONS FIRST Write your name, index number and class on all the work you hand in. Write in dark blue or black pen. You may use an HB pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. Approved calculators are allowed. Candidates will answer on the question paper. Answer all questions. The number of marks is given in brackets [ ] at the end of each question or part question. You should show all your working. The total number of marks for this paper is 80. Name of setter: Mr Christopher Sim For Examiner’s Use Parent’s Signature: ___________________________ Total 80 This paper consists of 15 printed pages including the cover page. [Turn over

2 1 (a) Convert the denary number 110 into binary number. Show your working. .......................................................................................................................... .......................................................................................................................... ......................................................................................................................[2] (b) Convert the hexadecimal number 19C into denary number. Show your working. .......................................................................................................................... .......................................................................................................................... ......................................................................................................................[2] 2 Lawrence has a computer that has a central processing unit (CPU) based on the Von Neumann model for a computer system. (a) Identify the component within the CPU that controls the flow of data. ......................................................................................................................[1] (b) Identify the component within the CPU where calculations are carried out. ......................................................................................................................[1] (c) Identify the set of wires responsible for the transport of data between components of computer. ......................................................................................................................[1]

3 3 Instructions executed by the computer can either be processed by a programming language or a machine code. (a) Give two reasons why a programmer would choose to write a program in using programming language instead of writing a machine code. 1 .................................................................................................