IGCSE COMPUTER SCIENCE: UNIT #1
EXAM QUESTIONS WITH COMPLETE
ANSWERS
What is the general rule for converting from denary to hexadecimal? - Answer-Divide by
largest power of 16 possible and do the same for each remainder until the remainder is
0. Convert each digit to its hexadecimal and put them together
How do you convert from binary from hexadecimal? - Answer-Convert each nibble to its
hexadecimal equivalent
What is hexadecimal used for? - Answer-Representing colours
MAC addresses
Debugging
Representing characters
Memory addresses
Assembly language
How is hexadecimal representing colours? - Answer-A 6 digit hex value is used with
each 2 digits representing an amount of a colour
How is hexadecimal used for MAC addresses? - Answer-12 hex digits are used with the
first 6 containing the ID number and the second 6 represent the serial number
How is hexadecimal used for debugging? - Answer-By viewing the hexadecimal output
(a hex dump) where bytes of data are output as a series of 2-byte hex values
How is hexadecimal used to represent characters? - Answer-To represent characters
not permitted within a URL (% indicates it's hex and 20 representing a space)
Why is hexadecimal used to represent memory addresses? - Answer-It is shorter than
representing them in binary
How is hexadecimal used in assembly language? - Answer-Representing instructions
and operands
What is the name given to a unique code for each character? - Answer-A code point
What is the most commonly used system to represent characters using binary codes? -
Answer-7 bit standard ASCII
How many different symbols can 7 bit standard ASCII represent? - Answer-128
, How is 7 bit standard ASCII stored in a computer? - Answer-As an 8 bit byte
What do extended ASCII sets do? - Answer-Make use of the unused 128 codes to
represent special characters in other language
What are character sets? - Answer-A particular range of characters and their code
points
What is a coded character set? - Answer-A complete set of characters and their code
points
What a character set allow? - Answer-To convert a binary code into a written language
character
How many characters can an ASCII character set store? - Answer-256
What is the difference between a letters upper and lowercase ASCII values? - Answer-
32
What does the Unicode character coding system use? - Answer-2 bytes per character
How many values can Unicode represent? - Answer-65,536
What is a code page? - Answer-One portion of the Unicode space
What does each code page represent in Unicode? - Answer-A language
What did a further extension of Unicode expand the scheme to? - Answer-21 bits
What is meant by sound being analogue? - Answer-They are made of waves that travel
through matter
What must be done to record and store sounds? - Answer-Convert them into digital
format
What does a sound card do? - Answer-Translates between a computer's digital
information and the outside world's analogue information
What does a microphone do? - Answer-Converts sound waves into voltage changes
What does a sound card do when plugged into a microphone? - Answer-Samples the
changing voltage at intervals (the sample rate) and covert each value into a binary
number
EXAM QUESTIONS WITH COMPLETE
ANSWERS
What is the general rule for converting from denary to hexadecimal? - Answer-Divide by
largest power of 16 possible and do the same for each remainder until the remainder is
0. Convert each digit to its hexadecimal and put them together
How do you convert from binary from hexadecimal? - Answer-Convert each nibble to its
hexadecimal equivalent
What is hexadecimal used for? - Answer-Representing colours
MAC addresses
Debugging
Representing characters
Memory addresses
Assembly language
How is hexadecimal representing colours? - Answer-A 6 digit hex value is used with
each 2 digits representing an amount of a colour
How is hexadecimal used for MAC addresses? - Answer-12 hex digits are used with the
first 6 containing the ID number and the second 6 represent the serial number
How is hexadecimal used for debugging? - Answer-By viewing the hexadecimal output
(a hex dump) where bytes of data are output as a series of 2-byte hex values
How is hexadecimal used to represent characters? - Answer-To represent characters
not permitted within a URL (% indicates it's hex and 20 representing a space)
Why is hexadecimal used to represent memory addresses? - Answer-It is shorter than
representing them in binary
How is hexadecimal used in assembly language? - Answer-Representing instructions
and operands
What is the name given to a unique code for each character? - Answer-A code point
What is the most commonly used system to represent characters using binary codes? -
Answer-7 bit standard ASCII
How many different symbols can 7 bit standard ASCII represent? - Answer-128
, How is 7 bit standard ASCII stored in a computer? - Answer-As an 8 bit byte
What do extended ASCII sets do? - Answer-Make use of the unused 128 codes to
represent special characters in other language
What are character sets? - Answer-A particular range of characters and their code
points
What is a coded character set? - Answer-A complete set of characters and their code
points
What a character set allow? - Answer-To convert a binary code into a written language
character
How many characters can an ASCII character set store? - Answer-256
What is the difference between a letters upper and lowercase ASCII values? - Answer-
32
What does the Unicode character coding system use? - Answer-2 bytes per character
How many values can Unicode represent? - Answer-65,536
What is a code page? - Answer-One portion of the Unicode space
What does each code page represent in Unicode? - Answer-A language
What did a further extension of Unicode expand the scheme to? - Answer-21 bits
What is meant by sound being analogue? - Answer-They are made of waves that travel
through matter
What must be done to record and store sounds? - Answer-Convert them into digital
format
What does a sound card do? - Answer-Translates between a computer's digital
information and the outside world's analogue information
What does a microphone do? - Answer-Converts sound waves into voltage changes
What does a sound card do when plugged into a microphone? - Answer-Samples the
changing voltage at intervals (the sample rate) and covert each value into a binary
number
