IGCSE COMPUTER SCIENCE: UNIT #1
EXAM QUESTIONS WITH COMPLETE
ANSWERS
What can one switch represent? - Answer-0 or 1
What is the term for converting data into binary? - Answer-Digitising
What is binary? - Answer-A numbering system using base 2
What is denary? - Answer-A numbering system using base 10 (normal)
What base does binary use? - Answer-Base 2
What is the maximum number 8 bit binary can represent? - Answer-255
What is the least significant bit in binary? - Answer-The furthest bit to the right
What is an overflow error? - Answer-An error that occurs when a computer cannot store
the result of a calculation in the memory space allocated for the task
What are registers? - Answer-Memory locations that have a specific purpose
How big is a registers capacity? - Answer-Very small
What are some examples of registers? - Answer-Controlling features of a smart-home
Lighting different segments in a digital LED display
A single ASCII character
A simple counter
What is the standard method for representing negative values? - Answer-Two's
complement
What is the most significant bit? - Answer-The bit furthest to the left
What bit is always used to represent a negative value? - Answer-The most significant bit
How do you make binary negative - Answer-Flip the most significant bit to a 1
Flip all the bits except the least significant bit
What do positive values always start with for two's compliment? - Answer-0
What do negative values always start with for two's compliment? - Answer-1
, What happens during a logical shift? - Answer-All the bits are shifted n spaces either left
or right
What happens to the original value when shifted left? - Answer-It is multiplied by the
amount of bit shifts ^2
What happens to the original value when shifted right? - Answer-It is divided by the
amount of bit shifts ^2 and removes the fraction (rounded down)
To multiply by values that are not powers of two what can be done? - Answer-Combine
shifts to have multiple shifts that are powers of 2
What is hexidecimal? - Answer-A numbering system that uses base 16
What does hexadecimal goes from and to? - Answer-0-F
Why is hexadecimal used? - Answer-It is easier to read than binary
What may hexadecimal numbers have written in front of them? - Answer-0x
How do you convert from 2-digit hexadecimal to denary? - Answer-Convert the most
significant bit and multiply by 16
Convert the least significant bit
Add together
What is the general rule for converting from hexadecimal to denary? - Answer-Multiply
each bit by 16^position-1 and add them together
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
EXAM QUESTIONS WITH COMPLETE
ANSWERS
What can one switch represent? - Answer-0 or 1
What is the term for converting data into binary? - Answer-Digitising
What is binary? - Answer-A numbering system using base 2
What is denary? - Answer-A numbering system using base 10 (normal)
What base does binary use? - Answer-Base 2
What is the maximum number 8 bit binary can represent? - Answer-255
What is the least significant bit in binary? - Answer-The furthest bit to the right
What is an overflow error? - Answer-An error that occurs when a computer cannot store
the result of a calculation in the memory space allocated for the task
What are registers? - Answer-Memory locations that have a specific purpose
How big is a registers capacity? - Answer-Very small
What are some examples of registers? - Answer-Controlling features of a smart-home
Lighting different segments in a digital LED display
A single ASCII character
A simple counter
What is the standard method for representing negative values? - Answer-Two's
complement
What is the most significant bit? - Answer-The bit furthest to the left
What bit is always used to represent a negative value? - Answer-The most significant bit
How do you make binary negative - Answer-Flip the most significant bit to a 1
Flip all the bits except the least significant bit
What do positive values always start with for two's compliment? - Answer-0
What do negative values always start with for two's compliment? - Answer-1
, What happens during a logical shift? - Answer-All the bits are shifted n spaces either left
or right
What happens to the original value when shifted left? - Answer-It is multiplied by the
amount of bit shifts ^2
What happens to the original value when shifted right? - Answer-It is divided by the
amount of bit shifts ^2 and removes the fraction (rounded down)
To multiply by values that are not powers of two what can be done? - Answer-Combine
shifts to have multiple shifts that are powers of 2
What is hexidecimal? - Answer-A numbering system that uses base 16
What does hexadecimal goes from and to? - Answer-0-F
Why is hexadecimal used? - Answer-It is easier to read than binary
What may hexadecimal numbers have written in front of them? - Answer-0x
How do you convert from 2-digit hexadecimal to denary? - Answer-Convert the most
significant bit and multiply by 16
Convert the least significant bit
Add together
What is the general rule for converting from hexadecimal to denary? - Answer-Multiply
each bit by 16^position-1 and add them together
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
