ACSBR 2019 P1

Prelim Examination 2019 1 Secondary 4 Express Computing 7155/01 Name: Class: Index Number: PRELIMINARY EXAMINATION 2019 SECONDARY FOUR EXPRESS COMPUTING PAPER 1 7155/01 2 HOURS INSTRUCTIONS TO CANDIDATES: Do not open this booklet until you are told to do so. Write your name and index number clearly in the spaces at the top of this page. Write in dark blue or black pen. You may use soft pencil for any diagrams, graphs or rough working. Do not use staples, paper clips, highlighters, glue or correction fluid. Approved calculators are allowed. Answer all questions. The number of marks is given in brackets [ ] at the end of each question or part of question. You should show all your working. The total mark for this paper is 80. This paper has 11 pages, inclusive of the cover page.

Anglo-Chinese School (Barker Road) Prelim Examination 2019 2 Secondary 4 Express Computing 7155/01

Anglo-Chinese School (Barker Road) Prelim Examination 2019 3 Secondary 4 Express Computing 7155/01 1 (a) Convert 32 KB into bytes. …………………………………………………………………………………….. [1] (b) Convert 3 MiB into bytes. …………………………………………………………………………………….. [1] 2 Draw a line to match the role to its correct description. Roles arithmetic logic unit ● address bus ● data bus ● control unit ● memory ● output ● Description ● Stores data, instructions and the result of processing for immediate use ● Transports required memory location from processor to memory; uni-directional ● Intermediate or final results produced by the computer; usually in the form of processed data ● Part of the processor that processes data by performing basic mathematical and logical operations [4] 3 Insert four of the following phrases in the correct space below. Metropolitan Area Network Internet protocol Router Wide Area Network Service Set Identifiers Network Interface Card (a) ……………………………………………...…. provides the hardware interface to enable the transfer of data between a device and a network. (b) ……………………………………………...….. is a 32-byte string that indicates a wireless access point (WAP) and all devices connected to it. (c) …………………………………………...…….. allows separate networks that use different network protocols to be connected together (d) ……………………………………………...…..: Network of computing devices typically spanning across two or more buildings within the same town or city.

Anglo-Chinese School (Barker Road) Prelim Examination 2019 4 Secondary 4 Express Computing 7155/01 [4]

Prelim Examination 2019 5 Secondary 4 Express Computing 7155/01 4 Your company is setting up a new office and you as the manager of the new office need to decide to install wireless or wired nework. Give one advantage and one disadvantage of a wireless network as compared to a wired network. Advantage……………………………………………………………………..……………… ...........…………………………………………………………………………..……………... ...........…………………………………………………………………………..……………... Disavantage……………………………………………………………………..……………. ...........…………………………………………………………………………..……………... ...........……………………………………………………………………………........... [4] 5 The use of technology has impact our lives in many areas. Describe two advantages and two disadvantages of the impact of technology on healthcare. Advantage 1 ……………………………………………………………………..………….... ...........…………………………………………………………………………..…………...… ...........…………………………………………………………………………..…………...… Advantage 2 ……………………………………………………………………..………….... ...........…………………………………………………………………………..…………...… ...........…………………………………………………………………………..…………...… Disavantage 1 ……………………………………………………………………..…………. ...........…………………………………………………………………………..…………...… . ..........…………………………………………………………………………..…………...… Disavantage 2 ……………………………………………………………………..…………. ...........…………………………………………………………………………..…………...… ...........…………………………………………………………………………..……….. [4]

Prelim Examination 2019 6 Secondary 4 Express Computing 7155/01 6 It is an increasing trend in online transactions such as i-banking and e-shopping. This has led to an increase in pharming. (a) Describe what pharming is and how it works. ...…………………………………………………………………………..…………...... ....…………………………………………………………………………..……… [2] (b) One way to avoid being pharmed is to ensure that public key encryption is used when submitting credit card or other sensitive information via the Internet. Explain how public key encryption works. ...…………………………………………………………………………..…………...... ...…………………………………………………………………………..………. [2] (c) Suggest another way to avoid being pharmed. ...…………………………………………………………………………..…………...... ...…………………………………………………………………………..………. [2] 7 Name two types of external storage that are commonly found in a computer system, list their corresponding example and describe each of them in terms of their advantage and disadvantage. Type 1…………………………………………………………………………..…………...… Example …………………………………………………………………………..…………... Description……………………………………………………………………..…………...… ...........…………………………………………………………………………..…………...… Type 2………………………………………………………………………..…………...…… Example …………………………………………………………………………..…………... Description……………………………………………………………………..…………...… ...........…………………………………………………………………………..………. [6]

Prelim Examination 2019 7 Secondary 4 Express Computing 7155/01 8 Study the Boolean statement: Q = 1 if (A = 1 AND B = 1) OR ( (B = NOT 1) AND C = 1) (a) Complete the truth table for the Boolean statement above. A B C Working space Q 0 0 0 0 0 1 0 1 0 0 1 1 1 0 0 1 0 1 1 1 0 1 1 1 [2] (b) Draw a logic circuit for the Boolean statement above. A B C Q

Anglo-Chinese School (Barker Road) Prelim Examination 2019 8 Secondary 4 Express Computing 7155/01 [4]

Prelim Examination 2019 9 Secondary 4 Express Computing 7155/01 9 Study the flowchart below. Complete the trace table for the flowchart. Trace table a b c d e output [6] Start a=0 b=1 c=0 d=9 e=2 e<d? c=a+b a=b b=c e=e+1 Output c End No Yes

Prelim Examination 2019 10 Secondary 4 Express Computing 7155/01 10 The spreadsheet below shows the information of a shopping list. (a) The spreadsheet above contains …….. rows and …….. columns. [1] (b) Write down the range of cells that has been merged. …………………………………………………………………………………… [1] (c) A formula =C4*D4 is entered in cell E4 to calculate the total price for five toothbrush. The formula is copied to complete column E. Write down the formula in cell E6. …………………………………………………………………………………… [1] (d) Write down the formula in cell E11 to calculate the Grand Total. …………………………………………………………………………………… [1] (e) When the value in cell D5 is changed, list the cell(s) that will change as a result of this. …………………………………………………………………………………… [1] (f) Customers who spent a grand total of $80 and above can qualify for a lucky draw. Write down a function in cell B11 to display Yes if the customer is qualified, display No if he is no. …………………………………………………………………………………… [1] t