WorksheetsA-Level Computer Science
Total questions: 162
Worksheet time: 2hrs 27mins
What subcategory of software does a virus checker belong to.
Operating System
Translators
Utilities
Defragmentation
Which of the following is not a resource managed by an operating system?
Processor
Memory
I/O Devices
Allocating Files on Secondary Storage
Provides Virtual Machine
Which layer of the TCP/IP stack determines which application layer software on the server should deal with a received request by using port numbers?
Application
Transport
Network
DataLink
In a DBMS, when a user starts to edit a record, others are prevented from accessing the record for the duration of the editing. What is this called?
(a)
Which form of transmission results in the clocks for the receiver and transmitter synchronising for the duration of a transmission?
(a)
Calculate the decimal equivalent of the normalised floating point representation number with an 8-bit mantissa and a 4-bit exponent, both stored using two’s complement.
1.0110010 0010
(a)
With an 8 bit mantissa and a 4 bit exponent, write the normalised floating point representation of the decimal value 0.15625
(a)
A particular computer system uses a 32-bit address bus and a 32-bit data bus. What is the maximum amount of memory, in bytes, that could be accessed?
(a)
Decrypt the ciphertext "QGOZRKT" using the Caesar cipher with the settings shown in the image.
(a)
Which of the following is not a condition required by the vernam cipher?
The key must be truly random.
The key must be transmitted with the data being encrypted/ rendered into ciphertext
The key must not be reused.
The key must be at least as long as the data to be encrypted/plaintext.
The key must be kept securely
Given the machine in the exampled image, how many commands can it store and work with?
(a)
Fill the blanks in the following explanation of the above assembly code.
Check if the value stored in memory location ___ is ___ times the value stored in memory location ___
(a)
The highest frequency component in a sound that is being sampled is 14,500 Hz. What should the minimum sample rate be?
(a)
Given an 8-bit mantissa and 4-bit exponent, write the normalised, two's complement representation of 58.5 in binary.
(a)
Which of the boolean equations above are incorrect? Select more than one.
Equation 1
Equation 2
Equation 3
Equation 4
Equation 5
Using odd parity, what is the parity bit for the following data? 0101011
(a)
A band is recording and digitising a song to make available as a download from their website.
The song lasts 3 minutes. The sample resolution is 16 bits and a sample rate of 44 kHz has been used. Calculate the minimum amount of storage space, in megabytes (MB), for the song and leave your answer with a precision of two decimal places.
(a)
Horatio is on Discord voice with his mates but his computer gives him a warning message that his microphone's ADC has failed. What is an ADC?
(a)
What is the name of the logic gate above?
(a)
Which type of computer architecture is typically used for digital signal processing?
(a)
SSID Stands for?
(a)
Some compilers produce this instead of an exe. This allows it to be platform independent.
(a)
The number of signal changes (which may occur) in a given period of time/in a second is known as...
(a)
The range of frequencies that can be transmitted across a network connection is known as...
(a)
RTS / CTS Are protocols which stand for?
(a)
In direct addressing mode, how many memory locations could a processor that used the instruction format shown above could potentially make use of?
(a)
Which type of high level programming languages will have instructions which are executed in a programmer-defined order?
(a)
What is the denary equivalent of the hexadecimal number D6?
(a)
Represent the decimal value -67 as an 8-bit two’s complement binary integer.
(a)
(a) communication is most notably evidenced with buses, where multiple bits are sent simultaneously.
Peripheral devices usually make use of __________ communication.
Serial
Parallel
What would be the primary key for the RaceEntryAndResult table?
(a)
The ASCII code for the numeric character "0" is 48, other numeric characters follow on from this in sequence. What character is represented by the bit pattern 0011 1001 if it is an ASCII code?
(a)
Convert 0011 1001 into Hexadecimal.
(a)
Calculate the minimum size of file that could be used to store the bitmap image in the figure above. Express your answer in bytes.
(a)
Calculate the decimal equivalent of the number.
(a)
Compress the above using Run-Length-Encoding.
(a)
Which theorem states that we need to be sampling at a frequency at least twice the rate of the highest frequency that can be present in the original signal?
(a)
Which of these represents a natural number?
A
B
C
D
None
Which logic gate is represented by this truth table?
(a)
Complete the truth tables for the OR and NAND gates. Put them in order from top to bottom. Separate your two answers with a space.
(a)
Complete the statement.
(a)
The processor in Ella’s computer has four cores running at 2.8 GHz and the processor in Josephine’s computer has one core running at 3.2 GHz.
Which computer would be faster at serial processing?
Ella's
Josephine's
Using abbreviations only, state one of the registers used in the fetch part of the F-E cycle.
(a)
Give the full name of RAM.
(a)
Translate &DD00 into denary
(a)
What is the result of performing the following logical operation?
00110000 OR 00000010
(a)
What is the result of performing the following logical operation?
NOT 01001111
(a)
What is the result of performing the following logical operation?
11000001 AND 00010011
(a)
What is the result of performing the following logical operation?
00000101 XOR 10001110
(a)
(a) addressing means the operand is the datum.
An attribute in one table which is a primary key attribute in another table is a (a) key
Another word for the mnemonic such as LDR, STR etc.
(a)
What is an edge-triggered D-type flip-flop used for?
For managing hardware resources.
For compiling code.
For performing arithmetic operations.
As a memory unit.
What is the relationship between hardware and software?
Hardware is the physical component, and software is the set of instructions.
Hardware and software are both physical components.
Hardware and software are both sets of instructions.
Hardware is the set of instructions, and software is the physical component.
What is system software?
Software that manages and controls computer hardware.
Software designed for end-users.
Software used for creating documents.
Software used for browsing the internet.
Which of the following is NOT a type of system software?
Operating systems
Word processors
Libraries
Utility programs
What is the role of an operating system?
To create web pages.
To write code.
To design graphics.
To hide the complexities of the hardware.
Which of the following is a low-level programming language?
Java
Python
Machine-code
JavaScript
What is an imperative high-level language?
A language used for database management.
A language used for web development.
A language that requires specific instructions to be given.
A language that is close to machine code.
What is the role of a compiler?
To manage hardware resources.
To translate high-level code into machine code.
To create graphical interfaces.
To interpret code line by line.
What is bytecode?
A type of system software.
A high-level programming language.
A type of hardware component.
The final output of some compilers.
What is the difference between source code and object code?
Source code is the compiled version, and object code is the written version.
Source code is written by programmers, and object code is the compiled version.
Source code is machine code, and object code is high-level code.
Source code is used for web development, and object code is used for system software.
Which logic gate has the output true only when both inputs are true?
AND
NOT
XOR
OR
What is the purpose of a truth table?
To write high-level code.
To manage hardware resources.
To display the physical components of a computer.
To show the output of a logic gate for all possible input combinations.
What is a half-adder used for?
To perform addition of two single-bit binary numbers.
To manage memory.
To perform subtraction.
To compile code.
What is an edge-triggered D-type flip-flop used for?
For managing hardware resources.
For compiling code.
For performing arithmetic operations.
As a memory unit.
What is De Morgan’s law used for?
To manage hardware resources.
To write high-level code.
To simplify Boolean expressions.
To compile code.
Which of the following is NOT a function of an operating system?
Managing I/O devices.
Creating web pages.
Allocating processors.
Managing hardware resources.
What is the primary function of a router in a network?
To provide wireless connectivity
To connect multiple networks and route network traffic
To store data for network users
To manage the security of a network
What is the primary purpose of the TCP/IP model?
To provide a set of rules for creating web pages
To ensure secure data transmission over the internet
To provide a standard for how data is transmitted over the internet
To manage the power consumption of networking devices
What does NAT (Network Address Translation) allow a router to do?
Increase the speed of the network
Convert between protocols like TCP and UDP
Allow multiple devices to share a single IP address
Provide encryption for data packets
The ASCII value for the letter 'a' in binary is 110 0001. What is the binary ASCII value for the letter 'e'?
110 0010
110 0100
110 0101
110 0110
The image shows how a modulo 11 check digit can be calculated.
Find the check digit for the string of digits 1 2 3 4 using modulo 11.
1
2
3
4
5
Which of the following is Nyquist's Theorem?
e = mc2
file size = sample res * sample rate
fs > 2fmax
Abstraction is the act of...
Adding extra detail to enable someone else to be able to solve the task without your help
Removing the detail that is important to solve the task
Removing all unnecessary detail to focus on what is important to solve the task
Creating an image that is similar to the object in question in some abstract way
Simplify the boolean expression 😆
!(A and B)
A or B
!A and B
A and !B
What is the difference between a static and dynamic data type?
Dynamic data types are fixed and static can change size
A dynamic data type can change size at run time, whereas static cannot
No difference, the are the same
How many bytes are there in a kibibyte?
1024000
10000
1000
1024
This is one of ....................... laws
Einstein's
Neptune's
Newton's
De Morgan's
What is the job of the logic circuit above?
Checks is a sensor is activated
Adds two binary numbers together
Subtracts one binary number from another
Adds two binary numbers and produces a sum and carry bit
The Current State is S0 and Input is 1
What is the OUTPUT and Direction
1, L
1, R
0, L
0, R
What is the Big O Notation of Merge Sort?
O(n)
O (n log n)
O(log n)
O(n2)
Which regular expression matches the FSM?
a?bc(dc)*
a|b(cd)+
a+bc(dc)?
a(b|c)d*c*
Select the strings that are matched by the regular expression:
a(b|c)?d
abcbcbcbcd
acd
ad
acccd
The Caesar cipher is an example of what type of cipher?
Substitution cipher
Transposition cipher
Public key encryption
Vernam cipher
The letter m has an ascii code of 1101101. As part of a Vernam cipher, the key 0101001 is applied to that letter. What is the resulting ciphertext?
1000100
0111011
1100101
1101001
The bit pattern 0110001 is sent with an even parity bit in the MSB position.
Which of these is the bit pattern receivedt?
00110001
10110001
01100011
01100010
The bitmap image of the lemming is 6 pixels by 10 pixels. There are 16 available colours for each pixel. Calculate the file size of the image (not including any metadata) in bytes.
30
120
22.5
60
Which of these are advantages of vector graphics over bitmap graphics?
Can be rescaled without distortion
(Usually) a smaller file size
Ideal for photographic images
Each pixel can be modified individually
Which of the following is Nyquist's Theorem?
e = mc2
file size = sample res * sample rate
fs > 2fmax
Abstraction is the act of...
Adding extra detail to enable someone else to be able to solve the task without your help
Removing the detail that is important to solve the task
Removing all unnecessary detail to focus on what is important to solve the task
Creating an image that is similar to the object in question in some abstract way
When would you use 'indefinite iteration'?
When you are unsure about how many times a loop will need to run to satisfy a condition
When you know exactly how many times you need to run the loop in the algorithm
When you want a different piece of code to run depending upon the value of a variable or condition
Simplify the boolean expression 😆
!(A and B)
A or B
!A and B
A and !B
What is the difference between a static and dynamic data type?
Dynamic data types are fixed and static can change size
A dynamic data type can change size at run time, whereas static cannot
No difference, the are the same
Which of the following is a 'divide and conquer' algorithm?
Linear search
Binary search
Merge sort
Bubble sort
How many comparisons will a Binary Search make to find the number 23 in the list?
3
4
2
10
How many passes will a Bubble Sort need to make to sort this list (in ascending order)?
1
2
3
4
What does the following describe?
The process of breaking a problem down into smaller problems that can be solved more easily.
Declaration
Functional Abstraction
Abstraction
Decomposition
How many bytes are there in a kibibyte?
1024000
10000
1000
1024
Which network topology is this?
Star
Bus
Mesh
Linear
This is one of ....................... laws
Einstein's
Neptune's
Newton's
De Morgan's
What is the job of the logic circuit above?
Checks is a sensor is activated
Adds two binary numbers together
Subtracts one binary number from another
Adds two binary numbers and produces a sum and carry bit
passes data over the physical network
transport layer
internet layer
link layer
application layer
retreieve emails from server
HTTP
FTP
SMTP
IMAP
Responsible for packet switching
TCP
UDP
IP
FTP
The Current State is S0 and Input is 1
What is the OUTPUT and Direction
1, L
1, R
0, L
0, R
Does Breadth-first search use a queue or a stack?
Stack
Queue
Both
neither
What is the Big O Notation of Merge Sort?
O(n)
O (n log n)
O(log n)
O(n2)
Which of these tree traversal methods is used to output the contents of a binary tree in ascending order?
Pre-Order
In-Order
Post-Order
Monastic Orders
A list must be in order for a Binary search to take place
True
False
Preorder Traversal of the tree
1 4 9 5 2 8 3
1 4 9 5 2 3 8
1 4 9 8 5 2 3
1 4 9 8 5 2 3
If the elements “A”, “B”, “C” and “D” are placed in a queue and are deleted one at a time, in what order will they be removed?
ABCD
DCBA
DCAB
ABDC
How many stacks are needed to implement a queue. Consider the situation where no other data structure like arrays, linked list is available to you.
1
2
3
4
Suppose a circular queue of capacity (n – 1) elements is implemented with an array of n elements. Assume that the insertion and deletion operation are carried out using REAR and FRONT as array index variables, respectively. Initially, REAR = FRONT = 0. The conditions to detect queue full and queue empty are
Full: (REAR+1) mod n == FRONT, empty: REAR == FRONT
Full: (REAR+1) mod n == FRONT, empty: (FRONT+1) mod n == REAR
Full: REAR == FRONT, empty: (REAR+1) mod n == FRONT
Full: (FRONT+1) mod n == REAR, empty: REAR == FRONT
If the sequence of operations - push (1), push (2), pop, push (1), push (2), pop, pop, pop, push (2), pop are performed on a stack, the sequence of popped out values
2,2,1,1,2
2,2,1,2,2
2,1,2,2,1
2,1,2,2,2
Which of the following is not an inherent application of stack?
Implementation of recursion
Evaluation of a postfix expression
Job scheduling
Reverse a string
What is the postfix equivalent for the following infix expression?
(2/4)*(5-6)
2 4 5 6 / - *
2 4 / 5 6 - *
2 4 / * 5 - 6
2 4 / 5 - 6 *
What name is given to the rules that define how symbols can be replaced by other symbols?
Construction rules
Production rules
Definition rules
Establishing rules
What type of object is enclosed in angle brackets in Backus-Naur form?
Definitive
Terminal
Non-terminal
Special
Why is it that Backus-Naur form is capable of representing some languages that cannot be represented by regular expressions?
Backus-Naur form supports definitions
Backus-Naur form supports Recursion
Backus-Naur form supports Selection
Backus-Naur form supports Loops
Which of the following examples uses valid recursion?
<Number> ::= <Digit> | <Digit><Number>
<Name> ::= <Forename><Surname>
<Age> ::= <Digit>|<Digit><Digit>
<Name> ::= <Name>
For the set "A = {1, 2, 3, 4, 5 }"
which is the correct set comprehension
A = {x | x ∈ ℕ ∧ 6 > x ≥ 1 }
A = | x ∈ ℕ ∧ 5 > x ≥ 1
A = (x | x ∈ ℕ A x ≥ 1 )
A = {x ∈ ℕ ∧ 1 > x ≥ 5 }
What is the "Cardinality" of a set?
number of elements of a finite set
number of elements of an infinite finite set
number of elements of a finite or infinite set
number of elements not in a given set
What data structure can be used with postfix expressions?
Queue
Hash Table
Vector
Stack
What is represented by ellipses in syntax diagrams?
Terminals
Non-Terminals
Selections
Definitions
What 3 Parts does a RFID system contain?
Ram, Power supply and Monitor
Wheels, Engine, Battery
Processor, Printer and Scanner
Tag, Reader and Antenna
What are the two types of RFID Tags?
Active and Passive
Aggressive and Passive
Wireless and Wired
Male and Female
Active or Passive: Is not powered and receives power from reader
Active
Passive
This is an image of which type of drive?
Hard Disk Drive
Optical Drive
Solid State Drive
CD Drive
Which type of storage uses a laser?
Magnetic
Optical
Solid State
A ferry departs from A(-25, 28). It takes 3 hours to reach its destination B(20, -32), travelling in as straight line with constant velocity. Distances are in km. Find the velocity vector of the ferry.
15i + 20j
15i - 20j
20i + 15j
20i - 15j
The case in which a key other than the desired one is kept at the identified location is called?
Hashing
Collision
Chaining
Open addressing
A hash table of length 10 uses open addressing with hash function h(k)=k mod 10, and linear probing. After inserting 6 values into an empty hash table, the table is as shown above.
Which one of the following choices gives a possible order in which the key values could have been inserted in the table?
46, 42, 34, 52, 23, 33
34, 42, 23, 52, 33, 46
46, 34, 42, 23, 52, 33
42, 46, 33, 23, 34, 52
Which of the following statement(s) is TRUE?
1) A hash function takes a message of arbitrary length and generates a fixed length code.
2) A hash function takes a message of fixed length and generates a code of variable length.
3) A hash function may give the same hash value for distinct messages.
1 only
1 & 3 only
2 & 3 only
3 only
quiz = {"Do you help out at home? ":"yes",
"Do you beleive in Santa? ":"yes"}
What type of data structure is an array?
Static and mutable
Dynamic and immutable
Static and immutable
When traversing a binary tree, which diagram is post-order?
Which of these is the correct definition of a pixel?
The smallest addressable element of an image
The smallest part of the screen that can be coloured
A square part of an image
One of the 'lights' on the computer screen
When is Run Length Encoding not very effective?
When there are lots of the same colour pixels in a row
When there are lots of colour changes in a row
When there are only two colours per row
When there are lots of colours in runs on the same row
The number of bits a system can send per second is bandwidth.
True
False
The time it takes for a bit to get from sender to receiver.
Network
Latency
Bandwidth
Bitrate
Suppose a circular queue of capacity (n – 1) elements is implemented with an array of n elements. Assume that the insertion and deletion operation are carried out using REAR and FRONT as array index variables, respectively. Initially, REAR = FRONT = 0. The conditions to detect queue full and queue empty are
Full: (REAR+1) mod n == FRONT, empty: REAR == FRONT
Full: (REAR+1) mod n == FRONT, empty: (FRONT+1) mod n == REAR
Full: REAR == FRONT, empty: (REAR+1) mod n == FRONT
Full: (FRONT+1) mod n == REAR, empty: REAR == FRONT
If the sequence of operations - push (1), push (2), pop, push (1), push (2), pop, pop, pop, push (2), pop are performed on a stack, the sequence of popped out values
2,2,1,1,2
2,2,1,2,2
2,1,2,2,1
2,1,2,2,2
What is the postfix equivalent for the following infix expression?
(2/4)*(5-6)
2 4 5 6 / - *
2 4 / 5 6 - *
2 4 / * 5 - 6
2 4 / 5 - 6 *
Why is it that Backus-Naur form is capable of representing some languages that cannot be represented by regular expressions?
Backus-Naur form supports definitions
Backus-Naur form supports Recursion
Backus-Naur form supports Selection
Backus-Naur form supports Loops
Which of the following examples uses valid recursion?
<Number> ::= <Digit> | <Digit><Number>
<Name> ::= <Forename><Surname>
<Age> ::= <Digit>|<Digit><Digit>
<Name> ::= <Name>
For the set "A = {1, 2, 3, 4, 5 }"
which is the correct set comprehension
A = {x | x ∈ ℕ ∧ 6 > x ≥ 1 }
A = | x ∈ ℕ ∧ 5 > x ≥ 1
A = (x | x ∈ ℕ A x ≥ 1 )
A = {x ∈ ℕ ∧ 1 > x ≥ 5 }
What is the "Cardinality" of a set?
number of elements of a finite set
number of elements of an infinite finite set
number of elements of a finite or infinite set
number of elements not in a given set
What data structure can be used with postfix expressions?
Queue
Hash Table
Vector
Stack
