Federal Board Class X Computer Science

SECTION “A”

Q.1. Insert the correct option.

i. What function is performed by CU (Control Unit)?

• Calculation
• Writing Data
• Controlling Data
• Performed logical operation

ii. CD writer is a/an

• Output device
• Input device
• I/O device
• Storage device

iii. What is the icon “My Computer” on Desktop and example of?

• Drive icon
• Application
• File icon
• System icon

iv. Which of the following statements transfers the control unconditionally?

• FOR — NEXT
• ON GOTO
• GOTO
• IF Then

v. What is “+0.66E–4″ an example of?

• Numeric data
• Alphabetic data
• Alphanumeric data
• Integer data

vi. What is 2′s complement of 000?

• 001
• 101
• 100
• 000

vii. What one is NOT a “non-impact” printer?

• Dot Matrix
• Inkjet
• Laser
• Electrostatic

viii. What is 1 Mega byte equal to?

• 1024 bytes
• 1024 Kilo bytes
• 1024 Giga bytes
• 1024 Tera bytes

ix. What is another name given to build in functions?

• Library
• String
• User defined
• Class

x. How much data can a 16 bit bus transfer?

• 1 byte
• 2 bytes
• 3 bytes
• 4 bytes

xi. What is the picture on computer screen composed of

• Lines
• Circles
• Pixels
• Dots

xii. What is the function of Ctrl+C in DOS?

• Copy
• Redo
• Exit
• Break

xiii. What will be the value returned by SGN (–8)?

• 1
• –1
• 0
• +1

ix. What does ASII stands for?

• American standard currency for information interchange
• American standard cod for information interchange
• American super computer for internation internet
• American standard code for internation internet

SECTION “B”

Q.2. Attempt all the questions. (39)

i. (a) Why were ICs used in third generation computers instead of transistors?
i. (b) Why is LCD monitor used in Laptop Computers?

ii. Perform the following conversions
(a). (4A) = (?) , (b). (1001) + (?) , (c) (534) = (?)

iii. (a) What is machine language? Why is it required?
iii. (b) State the function of a Scanner.

iv. In an office a clerk types letter and applications he verifies the hard copies of these documents and emails the soft copies to the concerned persons.
(a) What software will be helpful for the clerk?
(b) What output device does he need?
(c) Which technology will he need to send email?

v. State the output of the following program segment.

10 GOSUB 400
20 GOSUB 500
30 PRINT “ONE”
40 END
400 PRINT “TWO”
410 RETURN
500 PRINT “THREE”
510 RETURN

vii. (a) State the function of the COPY and DISKCOPY commands in DOS.
vii. (b) A$ is a string variable in Basic. Assign it any string constant.

viii. State the purpose of Karnaugh Map. Simplify the following function using Karnaugh Map:

ABC + ABC + ABC + ABC

OR

A two dimensional array FAX has two rows and four columns

05 – 10 – 15 – 20
25 – 30 – 35 – 40

(a) What are the value of (FAX (1,3) and FAX (2,1)?
(b) Which elements of FAX contain the number 30 and 20.

ix. Correct the errors in each of program segments.

10 FOR K = 1 TO 5
20 FOR J = 1 TO K
30 PRINT K + J
40 NEXT K
50 NEXT J
60 STOP

x. Write a Basic Program to draw a square without using Line Statement.

xi. Convert FOR — NEXT loop into WHILE-WEND loop.

10 FOR I = 1 TO 5
20 INPUT A(i)
30 NEXT I
40 END

xii. Read the following code

10 LET P = 0
20 LET Q = 0
30 WHILE P < 10
40 Q = Q + P
50 P = P + 1
60 WEND
70 END

Complete the sentence

(a) The output is stored in the variable ……………..
(b) The control variable is ……………..
(c) The no. of iterations is ……………..

xiii. Consider the flowchart and state
(a) What is output if a = 0?
……………………………….
(b) What is output if a = 90?
……………………………….

SECTION “C”

NOTE: Attempt all questions. (21)

Q.3. Write a program that reads radius ‘r’ of a cylinder with height ‘h’ and calculates its volume.
i. Analyze the problem and state one finding.
ii. Design a solution by writing an algorithm.
iii. Write GW-Basic code to solve the problem.

OR

Write a program to read a student’s marks in a subject and print the grades letter according to the scheme.

GRADE RANGE | LETTER GRADES
80 – 100 ………………… A
65 – 79 ………………….. B
50 – 64 ………………….. C
40 – 49 ………………….. D
< 40 ……………………… F

i. State which type of loop you think in the most suitable 1.5.
ii. Write a GW Basic code to solve the problem.
iii. Draw a flowchart of the program.

Q.4. What is a computer virus? Describe some of their activities. How can computer virus be checked in your disk?