Computer Studies Paper 1 Marking Scheme
KCSE CLUSTER TESTS 15
Computer Studies Paper 1
SECTION A (40 Marks)
Accept logical files as way files viewed of its contents and processing to be carried upon them.
-Where as physical files is the actual arrangement of the file content in storage media. 1mk each
2 marks
Uses of computer in
a) Financial institution
-Payroll system.
-Accounting system.
-Banking system. Award each ½ mk
b) Transport system.
-Accept air traffic control.
-Shipping control.
-Automobile traffic control. Award each½ mk.
2 marks
Techniques of using a mouse. Accept.
-Clicking.
-Double clicking.
-Right clicking.
-Drag and drop. Award each ½mk.
2 marks
(a)Virtual reality.
-Condition in which a person is psychologically immersed in an artificial environment generated by a computer system. Award 1 mk
(b)Sensory devices.
-Head gear/head mounted display.
-Gloves.
-Body suit.
-Virtual reality software. Award ½ mk each
3 marks
(a)Advantages of USB. Accept
-It supports wide range/variety of peripheral devices.
-Faster in data signal transmission.
-Provide quality data transmission over long distance. award 1mk
(b)Parallel cables faster than serial.
-Reasons
-they use asset of many conductors than serial. award 1 mk
4 marks
(a)Difference between MAN and WAN. Accept WAN
-Cover unlimited geographical area MAN cover limited area.
-It is expensive to set up unlike MAN.
-It is difficult to install than MAN.
-It is slow in data transmission than MAN. award 1mk each
(b)Components of LAN. Accept.
-Data communication media/cables
-Communication divine/NIC/modem.
-Network software/network o/s/network protocol. award ½mk each.
5 marks
Peripheral devices for Ps/2 port. Accept
-Mouse
-Keyboard award 1 mk
1 marks
Careers of computer hardware Accept
-technician
-hardware engineer.award 1 mk each
2 marks
Restriction to illegal entry. Accept
-use burglar proof doors.
-grill windows.
-restriction to strangers.
-alarms.
-security personnel. award 1mk each.
3 marks
(a)Keyboard key under state of ON/OFF. Accept.
-CAPSLOCK.
-NUMSLOCK.
-SCROL.
-INSERT award ½mk each.
(b)Precautions when connecting a hard disk. Accept
-The power cables is off/disconnected to computer.
-Wear antistatic material to discharge any static change of the body.
-Connect power supply cable to the drive.
-Connect drive to another board. award 1 mk
4 marks
(a)Accept
-Computer crime is complex to detect.
-It is not easy to find clear evidence.
-There are no witness.
-Few people know the management of computer crime. award1mk each.
(b)Autocorrect-automatically correct wrong spelt words and replace with correct one.
Auto complex-display a word when typing for characters.
4 marks
(a)(i)Search engine-program Accept
-Searches a document for specified keyboards and returns a list of documents where the keyboards were found. A ward 1 mk
(ii)System entropy-decay of system with time. award 1 mk
(b)Example of search engine.
-Google.
-Yahoo.
-Hotmail. award ½mk
3 marks
(a)Real time-process of data immediately as it arrives. award 1 mk
(b)Distributed data processing- processing of data to two or more computer physically located at separate sites but connected to central processing unlike real time.
3 marks
(a)Disadvantages of monolithic system. Accept
-Difficult to debug.
-It is not easy to learn.
-It is not flexible.
-It is not easy to modify. A ward 1 mk each
(b)Uses of
(i)Master pages.
-Designs providing for general layout to all other pages of publication. award 1mk
(ii)Tracking-used to change the visual denseness or openness of characters in a line. Award 1 mk
5 marks
SECTION B (60 Marks)
Answer question 15 and any other three questions from this section in the spaces provided.(a) (i)A=10x2=20
Year =1+2=3. ½ mk
A=20 ½
(ii)A=20x2=40
Year=3+2=5 ½ mk
A=40 ½ mk
(iii)A=40x2=80
Year=5+2=7 ½mk
A=80 ½mk
(iv)A=80x2=160
Year=7+2=9 ½mk
A=160 ½mk
P=160x9=1440 1mk
Pseudo code for flow chart.
(b)Start Initialize year, profit and amount
(A) Repeat A=A x profit
Year=yearx2
Output A
Until year ˃7 P=A x year
Output P Stop
Award ½mk each step overall sequence flow 2mks
A ward each 1mk any two.
(c)Advantages of high level languages.
-Are portable (not machine dependant)
-Are user friendly.
-Flexible.
-Easy to debug.
-Better documentation.
-Fast to code. Disadvantages.
-Program execution is slow.
-Require memory for compilation.
-Require language translator to machine readable form.
15 marks
(a)(i)R-crop tool.
(ii)Q- Text tool. award1 mk
(b) Methods of transforming objects.
Accept- rotate
-skew
-reflection award½mk each
(c)(i) 10111.111
111.011+
11111.010 award 1 mk
16 marks
(a)(i)Expert system- is software that stores the knowledge of human experts and is then used as consultant in a particular field.
(ii)Components of expert system.
-Knowledge base- database of particular field having procedures for solving a problem.
-Inference engine- software that applies the rule from knowledge base provided by the to draw conclusion.
(iii)User interface-screen that enables user interface with the system. Award each 1mk
(b)Impact of ICT in
(i)Environment Accept
-Energy consumption.
-Radiation/emission of harmful rays.
-Pollution-toxic substances/catridges/laptops award any two mks each.
(ii)Employment-creating new opportunities/job replacement. Shifting from one department to another. Job displacement. Award 1mk
(c)(i)Partitioning-diving a disk into logic drive to store data for security/safety ground. award1mk
(ii)Reason of partitioning disk. Accept
-To avoid loss of all data in one drive.
-To provide back up of data to system e.g operating systems stored separately. Award 1mk each
(d)(i)=product(B2:D2)
(ii)value.
(iii)135.
15 marks
(a)(i)Components of satellite.
-Transmitter earth station set uplink to the satellite data.
-Satellite orbit-receiving/amplifies and transmite signals to receiving earth station.
-Receiving earth station-receive sent signals sent from other side. Advantages of satellite.
-Spam large geographical area.
-Support remote areas.
-Medium is flexible without loosing network.
(ii)Mesh topology.
Data terminal equipment. Mesh-common topology used in WAN, they have many paths between different locations.
(b) (i)Advantages of mesh.
-Network operational even if a node breaks down.
-Network is reliable.
-Point to point connections optimizes output of data.
-Easy to trouble short.
-Faster data transmission.
(ii)Example of radio waves. Accept
-HF (high frequency)
-VHF (very high frequency)
-UHF (ultra-high frequency) award 1mk
(c) Reasons for best choice of optical cables.
-Low alternation.
-Very secured untappable interference.
-High band width hence carrying high capacity. Award 1mk
15 marks
(a)Moi- university
-Degree. Kenyatta
-Degree Nairobi
-Masters JKUAT
-Masters Maseno
-Degree Egerton
-Degree Mombasa polytechnic
-Higher Diploma Kisumu polytechnic
-Diploma. Eldoret polytechnic.
-Diploma. Kenya polytechnic
-Higher Diploma.
(b) Job replacement-loss of job.
Job Displacement-change of job but same company.
(c) Higher quality products/services.
Better decision making. Compete effectively.
Timely computations of tasks.
Enjoy benefits of global markets.
Sharing information.
Reduce redun
(d) Bank account records
- property records. Income tax records Medical records Legal records Bio data.
15 marks