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WorksheetsUnit 1: Digital Information (APCSP '25-'26 code.org)
Total questions: 88
Worksheet time: 2hrs 30mins
Convert the decimal 128 to binary:
10000000
01111110
10000001
11001100
Convert the decimal 65 to binary:
01100001
00100001
01000001
00100101
Convert the decimal 254 to binary:
11110000
11111100
11111111
11111110
Convert the binary number 00010001 to decimal:
17
27
37
47
Convert the binary number 11001100 to decimal:
224
134
104
204
Convert the binary number 00100100 to decimal:
26
36
46
56
Which of these is the correct sequence for the place values for binary numbers?
1, 2, 4, 8, 16, 32, 64, 128
1, 2, 4, 6, 8, 10, 12, 14, 16
1, 2, 3, 4, 5, 6, 7, 8
0, 1
How high can you count in binary?
As high as you want
Up to 128
Up to 2
Up to 256
During your Lesson 3 Activity in sending binary messages, you sent 4 bits to your partner while another 4 bits came back from them as well. This back and forth exchange took a total of 16 seconds. Calculate the bit rate of this entire transmission.
.5 bits/second
2 bits/second
4 bits/second
.25 bits/second
As you learned when creating your number system in Lesson 4, you must have the following for this system to work EXCEPT:
Can only include 1 and 0
An agreement on the fundamental ordering of the symbols
A set of unique symbols
What is the minimum number of bits you would need to encode the 26 letters of the alphabet plus a space -- for a total of 27 characters?
2 bits
3 bits
5 bits
6 bits
With regards to representing digital data, the same value (number) can have a different representation depending on the number system used to represented it.
TRUE
FALSE
8 bits is enough to represent 256 different numbers. How many total bits do you need to represent 512 (twice as many) numbers?
9 bits
10 bits
16 bits
17 bits
Look at the partial chart above of the ASCII values. According to ASCII character encoding, which of the following letters is represented by the 8-bit binary value: 0100 0010
ASCII Character A
ASCII Character B
ASCII Character D
The table does not contain the value presented by this binary number
With regards to black and white images, which of the following is TRUE?
A white pixel is represented by a "0" bit
"1" represents that pixel being turned on
"1" represents that pixel being turned off
The white pixel can be represented as either a "1" or a "0" bit
With regards to black and white images, which of the following is FALSE?
A black pixel is represented by a "0" bit
"0" represents that pixel being turned off
"1" represents that pixel being turned off
A white pixel is represented by the "1" bit
Which of the following is TRUE regarding lossless and lossy compressions?
An example of lossless compression is a .jpg file
Lossless uses inexact approximations while lossy does not·
You can completely reconstruct lossless but not lossy compression ·
You can completely reconstruct lossy but not lossless compression
Which of the following is TRUE regarding data compression?
Data compression is only useful for files being transmitted over the Internet
Regardless of the compression technique used, once a data file is compressed, it cannot be restored to its original size.
Sending a compressed version of a file ensures that the contents of the file cannot be intercepted by an unauthorized user.
There are trade-offs involved in choosing a compression technique for storing and transmitting data.
A student is transferring photos from her camera to her computer. The student notices that the saved photos on her computer are lower quality than the original raw photo on her camera.
Which of the following could be a possible explanation for the difference in image quality?
The saved image files were compressed with a lossy compression technique.
The saved image files were compressed with a lossless compression technique.
The saved image files were not compressed properly.
Some information is lost every time a file is saved on a computer.
An MP3 audio compression algorithm identifies frequencies and volume levels that are outside the range of human hearing and removes the data representing these frequencies from the original. This technique results in a smaller audio file that sounds exactly the same to the human ear.
This technique is an example of what type of compression?
Lossy
Lossless
Fast Fourier Transform compression
Tailored compression
You can reverse a transformation process and re-create the original message. What kind of data compression is that?
lossless
lossy
There are trade-offs involved in choosing a compression technique for storing and transmitting data.
True
False
Sending a compressed version of a file ensures that the contents of the file cannot be intercepted by an unauthorized user.
True
False
A student is transferring photos from her camera to her computer. The student notices that the saved photos on her computer are lower quality than the original raw photo on her camera.
Which of the following could be a possible explanation for the difference in image quality?
The saved image files were compressed with a lossy compression technique.
The saved image files were compressed with a lossless compression technique.
The saved image files were not compressed properly.
Some information is lost every time a file is saved on a computer.
Adding a bit to a binary number...
...doubles the number of values that can be represented.
...increases the number of values that can be represented by 1000.
...increases the number of values that can be represented by 2.
...squares the number of values that can be represented.
How many bits would be needed to count all of the students in a particular class (if the number of students in class is 33)?
4
5
6
7
Each time we add another bit, we can make three times as many numbers as before.
True
False
Which of the following is FALSE regarding decimal and binary systems?
Both systems use the concept of place value
While the binary number system uses ten digits (0-9), the decimal numbers system only uses two (0 and 1)
In both systems, we can calculate each digit's value by multiplying the digit with its matching power of 2 or 10. The sum is the total value of the number.
Each digit in the decimal number system corresponds to a power of 10, whereas each digit in the binary number system corresponds to a power of 2.
When using bits to represent fractions of a number, which of the following is TRUE?
(A) It is possible to represent all possible fractions
(B) The inability to represent numbers exactly results in roundoff errors
Both (A) and (B) are True
Both (A) and (B) are False
Assume your friend just sent you 32 bits of pixel data (just the 0s and 1s for black and white pixels) that were encoded after sampling an image. Choose the two statements that are true.
The 32 bits of pixel data is enough to produce the image using the widget. Nothing else is needed
The digital image would be an exact copy of the analog image
The correct width and height must be input into the pixelation widget to produce the image
The fact that only 32 bits were used to represent the image indicates relatively large sample squares were used. The digital image may vary from the analog image significantly.
Which of the following would result in a better digital approximation of an analog black and white image?
Increasing the size of each sample square, thus decreasing the number of samples taken
Decreasing the size of each sample square, thus increasing the number of samples taken
Using fewer bits to represent the image.
Decreasing the size of each sample square, thus increasing the number of samples taken
Which statement about analog and digital images is true?
With advances in technology, digital images look exactly like the analog images they represent
Sampling an analog image more frequently produces a digital image with a better representation
Analog images come from data that is measured at regular intervals
Digital images come from data that is measures continuously
The Digital Public Library of America is a US project aimed at providing public access to digital holdings in order to create a large-scale public digital library. This would be an example of which of the following?
Open Access
Open Source
Creative Commons
Intellectual Property
OpenTTD is a software video game where developers are able to create complicated rail networks while allowing the players to find their own solutions and designs (Source: DesignRush). This would be an example of which of the following?
Open Access
Open Source
Intellectual Property
Creative Commons
A patent gives its owner the legal right to exclude others from making, using, or selling an invention for a limited period of years in exchange for publishing an enabling public disclosure of the invention . This would be an example of which of the following?
Open Access
Open Source
Intellectual Property
Creative Commons
Pixabay.com is an international, free-to-use website for sharing photos, illustrations, vector graphics, film footage and music. Many of the thousands of photographers & graphic designers that put their images on this site want specific rules on how their images will be used (i.e. not having their images used for commercial purposes). Which of the following should be used specifically for these situations?
Open Access
Open Source
Intellectual Property
Creative Commons
Which of the following is FALSE regarding intellectual property?
Intellectual property can include images, written publications, and video creations
When you create something digitally and leave it on the open web with no restrictions of how it can be used, anyone can use your creation without fear of legal consequences
As the creator of something from your computer, you have complete control of how your creation gets used by others
For something you create and place online, you don't have to have a label of "All Rights Reserved" in your creation to have copyright protection
With regards to sounds, if you want a higher quality sound, you pick a 32-bit audio or an 8-bit audio. More bits means a higher range of numbers.
True
False
When referring to RGB color, if we have 3 bits to represent each color (of red, green, and blue), we would have how many color choices for each pixel?
4
8
16
32
What is the highest value you can count to using 5 bits?
15
16
31
32
What is the the binary equivalent of 0.75?
000001.00 (because of rounding up)
000000.01
000000.111
000000.11
Roundoff errors occur when bit arrangements can’t represent numbers as intended. That being said, a binary number can be made for ANY decimal (such as 0.36).
True
False
What is the the binary equivalent of 0.50?
000001.00 (because of rounding up)
000000.10
000000.11
000000.01
Lisa takes a picture with her smartphone which she subsequently posts online. Allen finds the picture online and posts a copy of it on his website with an attached Creative Commons license. Which of the following best describes who owns the photo?
Allen owns the photo because only holders of a Creative Commons license can own works online.
Lisa owns the photo because she was the original creator and did not license the work.
Lisa owns the photo because it was granted a Creative Commons license by another person online.
Both own the photo because creating a copy makes it her intellectual property.
Which of these binary (base-2) numbers is the smallest?
1000 0001
1100 0001
0110 0110
0001 1111
Convert the binary (base-2) number 0011 0001 to decimal (base-10).
32
64
49
121
Ryan is designing an app that needs to quickly send low quality photos between users. Most smartphones take much higher quality photos than Ryan needs for his app. Which answer best describes the type of compression Ryan should choose and why?
Lossy compression since it typically results in smaller data sizes.
Lossless compression since it ensures perfect reconstruction of the photo.
Lossy compression since it ensures perfect reconstruction of the photo.
Lossless compression since it typically results in smaller data sizes.
Lucy is completing a project as part of a science class using materials she found online. Which of the following is MOST LIKELY to lead to legal consequences?
Modifying a piece of open source software.
Using open access research for which she does not acquire a license.
Failing to publish her work under a Creative Commons license
Using images posted online by another student without permission or citation.
Which of the following is true of intellectual property?
Information created on a computer is not owned by anyone since only analog information is protected under copyright law.
You do not need to cite work created by someone else if both the original work and your use of it are in digital form.
Creative Commons enables content creators to freely distribute their otherwise copyrighted work.
Creative Commons has severely hindered broad and open access to digital information
Jorge is sending a large image file to a friend as part of a shared classroom project. Which of the following is most likely true if Jorge opts to compress the image before sending it?
The image can no longer be represented using bits.
The image will have been converted into an analog form.
The image will require more pixels to display it on the screen.
The image will require fewer bits in order to be represented.
Which of the following is true of lossy and lossless compression algorithms?
Lossy compression algorithms are used when perfect reconstruction of the original data is important.
Lossy compression algorithms are typically better than lossless compression algorithms at reducing the number of bits needed to represent a piece of data.
Lossless compression algorithms are only used to compress text data.
Lossless compression algorithms only allow for an approximate reconstruction of the original data.
Which of the following is true of how computers represent numbers?
With a fixed number of bits some numbers are too large to represent in a computer which will lead to overflow errors.
Using a fixed but large number of bits can eliminate the possibility of round off error when representing numbers in binary
Using a fixed but large number of bits, for example 128, eliminates the possibility of overflow errors.
With a large but fixed number of bits it is possible to eliminate either round-off errors or overflow errors, but not both.
Your computer uses 4 bits to represent decimal numbers (0, 1, 2, 3 and so on) in binary. What is the SMALLEST number for which an overflow error occur?
14
15
16
17
When visiting a museum Sue takes a photo of a painting with a smartphone which stores the photo as an image file. Which of the following best describes the differences between the painting itself and the photo of the painting stored on the smartphone?
Both the painting and the photo are analog
Sampling can be used to determine whether the analog image is an accurate representation of the painting
The phone can represent the photo in either digital or analog formats depending on the sampling technique that is used
The photo is a digital representation of the analog painting
Which of the following best describes how computing devices represent information?
A computer will either represent information as bits or bytes but not both
A computer represents data as a byte which is either a 0 or a 1
A computer represents data as bits which is either a 0 or a 1
A computer represents information as bits which contain 8 bytes.
A raw digital sound file samples a sound wave at some interval and measures the height of the wave at each point. Thus, raw sound is recorded as a list of numbers.
In very broad terms the MP3 audio compression algorithm identifies frequencies and volume levels - low and high - that are outside the range of human hearing and removes the data representing these frequencies from the original. This technique results in a smaller audio file that sounds exactly the same to the human ear.
This technique is an example of what type of compression?
Lossy compression
Lossless compression
Fast Fourier Transform compression
Tailored compression
the fundamental unit of a digital image, typically a tiny square or dot that contains a single point of color of a larger image
Image
Pixel
metadata
Pie Chart
Consider the following three binary numbers:
01010
010000
1110
Which of the following lists the numbers in order from least to greatest?
010000
1110
01010
01010
1110
010000
01010
010000
1110
1110
01010
010000
The color widget uses 3 bytes of metadata. The first two bytes indicate the width and height of the image. The next byte indicates the number of bits that will be used to represent color. How many bits is used to represent color given the metadata (in binary) 00001000 00001000 0001001
3 bits
6 bits
9 bits
12 bits
Which of the following is irreversible?
lossy compression
lossless compression
abstraction
RLI
Innovation
A new or improved idea, device, product, etc, or the development thereof
A way of representing information using only two options
· A contraction of "Binary Digit"; the single unit of information in a computer, typically represented as a 0 or 1
Time it takes for a bit to travel from its sender to its receiver.
Which of the following is a reason to use lossy compression?
You want the compressed file to be larger than the original.
You want the highest quality audio file possible, with no modifications.
You want the highest quality image file possible, with no modifications.
You want to save space and are not concerned if the file is the highest quality possible.
ASCII
Having multiple backups to ensure reliability during cases of high usage or failure
A group of computers and servers that are connected to each other.
American Standard Code for Information Interchange; the universally recognized raw text format that any computer can understand
A type of computer that forwards data across a network
Abstraction
American Standard Code for Information Interchange; the universally recognized raw text format that any computer can understand
A simplified representation of something more complex. Abstractions allow you to hide details to help you manage complexity, focus on relevant concepts, and reason about problems at a higher level.
A group of computers and servers that are connected to each other.
A type of computer that forwards data across a network
Bit
A set of rules governing the exchange or transmission of data between devices.
The number of bits that are conveyed or processed per unit of time. e.g. 8 bits/sec.
Time it takes for a bit to travel from its sender to its receiver.
A contraction of "Binary Digit"; the single unit of information in a computer, typically represented as a 0 or 1
Binary:
A set of rules governing the exchange or transmission of data between devices.
a simplified representation of something more complex. Abstractions allow you to hide details to help you manage complexity, focus on relevant concepts, and reason about problems at a higher level.
A way of representing information using only two options
having multiple backups to ensure reliability during cases of high usage or failure.
online research output free of any and all restrictions on access and free of many restrictions on use, such as copyright or license restrictions
Open Access
Open Source
Open Door
Creative Commons
programs that are made freely available and may be redistributed and modified;
Open Source
Creative Commons
Expired Copyright
Downloadable Software
public copyright license that enables the free distribution of an otherwise copyrighted work. This is used when the content creator wants to give others to right to share, use and build upon the work they have created;
Copyright Infringement
Plagiarism
Creative Commons
Crowdsourcing
Which of the following statements about sampling is incorrect?
Sampling is a process that can be used to compress an image.
Sampling is a process for turning an analog image into a digital image.
When smaller samples are used, the resulting file will require fewer bytes.
Each pixel of the analog image is coded as one color, and cannot be more than one color.
ASCII is an abstraction because
it allows the user to know the binary code for each character.
the user can type letters and other characters without knowing the binary code assigned to them.
it helps the user convert the decimal representation of a letter to the binary representation for the letter.
the user can read a binary message and translate it into characters.
A computer program is using 4 bits to represent an integer. When the program adds the decimal numbers 10 and 6, the result is 0000. Which of the following describe the result? (Select all that apply)
The number 16 in decimal is 0000 in binary.
An overflow error occurred.
a roundoff error occurred.
You cannot represent the number 16 with 4 bits.
Which of the following are true about how analog data is converted to digital data?
The digital version is a representation of the analog, but cannot contain all of the details.
To make the digital version be a more accurate representation of the analog data, the process should use fewer bits to represent each sample.
A longer interval between measured samples means more details will be captured in the conversion from analog to digital.
The digital version contains all of the details of the analog data, as long as enough storage capacity is available.
