Gozo College Boys` Secondary Victoria
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1. Gozo College gor Boys Secondary ii Victoria Gozo Malta aid Ninu Cremona Half Yearly Examination 2012 2013 Subject COMPUTING Form 4 Track 3 Time 1 hr 30 min INDEX No Instructions to Candidates Answer ALL questions in Section A and Section B on this paper Calculators are NOT allowed Good English and orderly presentation are important pore meio e e Ps a te Use this Section A Answer ALL questions margin for rough work only 1 An 8 bit register of a computer system contains the binary number 10011 a Whatis a register 2 b What may be done to the bits in the register to quickly double multiply by 2 the value of the number 1 c Show how the result of part b is stored in the 8 bit register 1 d Convert result of part b to decimal 1 2 Data is represented using the binary number system a Use 2 s complement arithmetic and an 8 bit register to work out 120 31 3 Answer b What situation arises 1f the result of an addition operation does not fit in a 1 register c Which other mathematical function may also result in a similar situation to the 1 one mentioned in question b Computing Track 3 Form 4 2013 Page 2of10 Use this 3 Two s Complement Binary and Unsigned Binary are two ways how numbers and data can margin for be represented in computing rough work only a What is the smallest binary number that can be represented i2. 10 fern System out printin System out printIn The total is tot System out printf The average is 2f n aver Computing Track 3 Form 4 2013 Page 7of10 Use this a Identify the TWO loop constructs that are used in this program margin for rough work only Loop 1 2 Loop 2 b The user cannot enter a mark which is less than 0 However the user CAN enter a mark which is greater than 100 Identify the instruction which needs to be modified and write down a new instruction that you would write instead to make the program reject marks which are greater than 100 or less than 0 Instruction to be modified 2 New instruction c Re write the instructions x x 1 and tot tot mark using different arithmetic operators 2 X X 1 tot tot mark d What is type casting 2 Identify an instruction from the program where type casting is taking place 1 e The last instruction is System out printf The average is 2f n aver i Why was the command printf used instead of println 3 1i What would be the difference if 2f is replaced by 4f 111 What is the function of n in this instruction and what is it called f In the above program there are four followed by dotted lines 1 1 What are these four used for a Computing Track 3 Form 4 2013 Page 8of10 Use this 1i In the space below write down the appropriate text to replace the dotted
3. ban annie lines only ee me 2 rereeeni a 2 ae 13 The system life cycle is the process involved in the development of a new computerised system a Write down the following system life cycle stages in order programming and documentation feasibility study system maintenance 3 control and review present system study implementation and change over system design I 2 b Provide a reason to show why the systems analyst has to undertake each of the following three tasks Feasibility study 2 Control and review _ 2 Computing Track 3 Form 4 2013 Page 9of10 Use this Present system study ___ margin for rough work 2 only c Suggest two methods that the system analyst can use to collect the necessary information Method 1 2 Method 2 d Differentiate between Parallel and Direct changeover methods stating advantages and disadvantages of each 4 Computing Track 3 Form 4 2013 Page 10o0f10
4. n i a 10 bit two s complement register 2 ii a6 bit unsigned binary register b What is the largest number that can be represented in an 8 bit two s complement register Give your answer both in decimal and binary 1 Decimal Binary c Provide two reasons for storing numbers in two s complement and not as unsigned binary numbers l 2 2 4 Give the truth table and Boolean expression for the following logic circuit Boolean Expression 2 Answer Truth Table 3 Computing Track 3 Form 4 2013 Page 3o0f10 Use this 5 A mayor would like to create a binary code for every property house flat mar ior maisonette in his town using 7 bits rough work only a What is the maximum number of properties that can be coded using 7 bits 2 b He realised that he does not have enough codes and would like to double the number of codes available What can he do to do this 2 c The mayor decided to represent the codes in hexadecimal instead of binary Why would he do that 1 6 Using JAVA complete the following code to display the first 10 multiples of a number num entered by the user If 4 is entered by the user the multiples 4 8 12 16 40 are displayed class Multiples public static void main String args int num mI 7 Documentation is a very important aspect of a new computerised system a What is the main difference between the User Manual and the other ma
5. nuals in 1 terms of the vocabulary used Computing Track 3 Form 4 2013 Page 4of10 Use this b Mention TWO key items that one would expect to find in the Technical margin for Documentation rough work only 2 c Mention TWO situations that could arise that would require the use of the Program Documentation 2 8 A gate giving access to a car park rises if the car park is not full and a parking ticket is inserted in the machine Let A represent car park full Let B represent car park ticket inserted Draw the logic circuit and truth table of the gate s function G where open 5 9 Amongst all kinds of programming errors logic errors are said to be the hardest to trace and debug a Why are logical errors considered to be the worst 2 Computing Track 3 Form 4 2013 Page 5o0f10 Use this b Give one example of a logical error margin for rough work only 1 c Name and describe a tool that programmers use to identify logic errors 2 10 The following is a simple Java class that uses lejos instructions to control a robotic car The following instructions move the car forward and then turn it 90 degrees to the left public class Turn90Degrees public static void main String args LCD drawString Move amp Turn 0 0 Motor B regulateSpeed true Motor C regulateSpeed true Motor B setSpeed 300 Motor B setSpeed 300 Motor B forward Motor C forwa
6. rd Timer sleep 1000 Motor B stop Timer sleep 1000 Motor C stop a What is the method that controls the car s speed called 1 b What is the function of the instruction Timer sleep 1000 2 c Write down the instructions you would change from the above code so that your car turns to the right instead of to the left 2 Computing Track 3 Form 4 2013 Page 6of10 Use this margin for rough work only 11 The following is part of a JAVA program that works out the area of a circle System out printIn Enter radius of circule rad keyboard readInt area PI rad rad a The variables rad and area have to be declared Write down the data type which is suitable for these variables Variable rad Datatype 2 Variable area Datatype b Write down the instruction to declare PI as a constant equal to 3 142 2 c Rewrite the instruction where the area is calculated using the Math class to work out the square of the radius 1 Section B Answer BOTH questions 12 Below is a simple JAVA class that deals with the marks of a group of students public class Marks public static void main String args int x int mark int tot O eee for x 1 x lt 11 x x 1 do a RRR AT System out print Enter a mark between 0 and 100 mark Keyboard readInt while mark lt 0 tot tot mark 1 eT double aver double tot
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