Carrollton High School AP Computer Science

What is the most important quality of lossless compression? A. The data is transformed to usually make it smaller. It can always be re-constructed back to the original. B. The data is transformed to always make it smaller. It can always be re-constructed back to the original. C. The data is transformed to usually make it smaller. It cannot always be re-constructed back to the original. D. The data is transformed to always make it smaller. It cannot always be re-constructed back to the original.

A). The data is transformed to usually make it smaller. It can always be re-constructed back to the original.

Which of the following binary (base-2) numbers is LARGEST? A. 11000000 B. 01111111 C. 00000001 D. 10111111

A. 11000000 (Explanation: Since all of these are 8-bit binary digits, the leftmost place value is the 128s place. 11000000 and 10111111 both have a 1 in the 128s place. Since 11000000 has a 1 in the 64s place and 10111111 does not, 11000000 is larger no matter the rest of the digits.)

Convert the binary (base-2) number 1001 to decimal (base-10). A. 9 B. 10 C. 16 D. 17

A. 9

Which of the following is NOT true of how computers represent complex information? A. Computing devices use patterns of bits to represent complex information B. Abstraction helps represent complex information by surfacing complexity that might otherwise be hidden C. Depending on context the same sequence of bits may represent different types of information D. Common abstractions that are represented by computing devices include numbers, characters, and color.

B. Abstraction helps represent complex information by surfacing complexity that might otherwise be hidden (Explanation: Abstraction helps by hiding complexity rather than surfacing it. For example, you don't have to know all the details about how a car works in order to operate it.)

Arman takes a picture with his smartphone which he subsequently posts online. Beatrice finds the picture online and posts a copy of it on her website with an attached Creative Commons license. Which of the following best describes who owns the photo? A. Beatrice owns the photo because only holders of a Creative Commons license can own works online. B. Arman owns the photo because he was the original creator and did not license the work. C. Arman owns the photo because it was granted a Creative Commons license by another person online. D. Both own the photo because creating a copy makes it her intellectual property.

B. Arman owns the photo because he was the original creator and did not license the work. (Explanation: Since Arman is the original creator of the photo, the photo is his intellectual property.)

Which of the following is true of lossy and lossless compression algorithms? A. Lossy compression algorithms are used when perfect reconstruction of the original data is important. B. Lossy compression algorithms are typically better than lossless compression algorithms at reducing the number of bits needed to represent a piece of data. C. Lossless compression algorithms are only used to compress text data. D. Lossless compression algorithms only allow for an approximate reconstruction of the original data.

B. Lossy compression algorithms are typically better than lossless compression algorithms at reducing the number of bits needed to represent a piece of data. (Explanation: Since lossless compression keeps all the information from the original item, it cannot do as good a job of reducing the number of bits as lossy compression where some of the original information is lost.)

Which statement about analog and digital images is true? A. With advances in technology, digital images look exactly like the analog images they represent. B. Sampling an analog image more frequently produces a digital image with a better representation. C. Analog images come from data that is measured at regular intervals. D. Digital images come from data that is measures continuously.

B. Sampling an analog image more frequently produces a digital image with a better representation.

When visiting a museum Lian 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? A. Both the painting and the photo are analog B. The photo is a digital representation of the analog painting C. Sampling can be used to determine whether the analog image is an accurate representation of the painting D. The phone can represent the photo in either digital or analog formats depending on the sampling technique that is used

B. The photo is a digital representation of the analog painting (Explanation: A painting is an analog because it's something with continuous representation. A digital photo changes discreetly at every pixel using a finite set of colors.)

Which of the following is true of how computers represent numbers? A. Using a fixed but large number of bits can eliminate the possibility of round off error when representing numbers in binary B. With a fixed number of bits some numbers are too large to represent in a computer which will lead to overflow errors. C. Using a fixed but large number of bits, for example 128, eliminates the possibility of overflow errors. D. With a large but fixed number of bits it is possible to eliminate either round-off errors or overflow errors, but not both.

B. With a fixed number of bits some numbers are too large to represent in a computer which will lead to overflow errors. (Explanation: With a fixed amount of bits, no matter how many, at some point the largest possible value will be reached, with 1s for all the bits. Representing the next largest number will lead to an overflow error and the odometer will start back at all 0s.)

Pick Two: If the post office delivered mail exactly like the routers deliver messages on the Internet, which of the following statements would be true? A. One mailman would be responsible for delivering a letter from sender to receiver B. The mailman would sometimes take a different path to deliver each letter to your home C. Letters would be written on the outside of the envelope for all to read instead of letters put inside envelopes D. Your mail could not be delivered if a road your mailman was planning to take were under construction.

Both A. Each device or computer on the Internet is assigned a unique IP address. and C. Letters would be written on the outside of the envelope for all to read instead of letters put inside envelopes

Pick the two statements that are true about the Internet Protocol (IP): A. Each device or computer on the Internet is assigned a unique IP address. B. IP is a secret protocol shared between the sender and receiver. C. Each network on the Internet uses its own protocol to address messages. D. In order to communicate two devices on the Internet must have the same IP address. E. IP is the shared way that all devices and computers label their messages with the sender and receiver's addresses.

Both A. Each device or computer on the Internet is assigned a unique IP address. and E. IP is the shared way that all devices and computers label their messages with the sender and receiver's addresses.

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? A. 14 B. 15 C. 16 D. 17

C. 16 (Explanation: The 4-bit binary number 1111 represents the decimal number 15. Counting up to the next number, 16, will cause the 4-bit binary number to overflow to 0000 just like an odometer.)

Which of the following best describes how computing devices represent information? A. A computer will either represent information as bits or bytes but not both B. A computer represents data as a byte which is either a 0 or a 1 C. A computer represents data as bits which is either a 0 or a 1 D. A computer represents information as bits which contain 8 bytes.

C. A computer represents data as bits which is either a 0 or a 1 (Explanation: The definition of a bit: a contraction of "Binary Digit"; the single unit of information in a computer, typically represented as a 0 or 1.)

Which of the following is true of intellectual property? A. Information created on a computer is not owned by anyone since only analog information is protected under copyright law. B. 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. C. Creative Commons enables content creators to freely distribute their otherwise copyrighted work. D. Creative Commons has severely hindered broad and open access to digital information

C. Creative Commons enables content creators to freely distribute their otherwise copyrighted work. (Explanation: Creative Commons works within copyright law. It allows creators to grant permission to everyone in the world to use their work in certain ways.)

Convert the decimal (base-10) number 20 to binary (base-2). A. 10010 B. 00101 C. 11000 D. 10100

D. 10100 (Explanation: Using your Flippy Do, the first place value that fits into 20, going from left to right, is 16, so the 16s place becomes a 1. Next, 4 remains and so you put a 1 in the 4s place. (1 x 16) + (0 x 8) + (1 x 4) + (0 x 2) + (0 x 1) = 20)

How many total numbers can be represented with an 8-bit binary (base-2) system? A. 127 B. 128 C. 255 D. 256 Explanation: Binary is a base 2 number system. With each new bit, we double the amount of unique numbers we can make. With 7 bits, we can make the decimal numbers 0 to 127 (0000000 to 1111111), for a total of 128 unique numbers. When we go up to 8 bits, we can make the decimal numbers 0 to 255 (00000000 to 11111111) for a total of 256 unique numbers.

D. 256 (Explanation: Binary is a base 2 number system. With each new bit, we double the amount of unique numbers we can make. With 7 bits, we can make the decimal numbers 0 to 127 (0000000 to 1111111), for a total of 128 unique numbers. When we go up to 8 bits, we can make the decimal numbers 0 to 255 (00000000 to 11111111) for a total of 256 unique numbers.)

Which of the following is true regarding the way information is transmitted on the Internet? A. Information flows on a dedicated direct connection from the sender's device to the receiver's device using binary electrical signals. B. If a single packet is dropped, the entire file must be resent. C. Because of the reliability of the Internet, packets always arrive in the same order they were sent. D. Information does not travel in one piece, but rather as a datastream of packets.

D. Information does not travel in one piece, but rather as a datastream of packets.

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? A. Lossless compression since it ensures perfect reconstruction of the photo. B. Lossy compression since it ensures perfect reconstruction of the photo. C. Lossless compression since it typically results in smaller data sizes. D. Lossy compression since it typically results in smaller data sizes.

D. Lossy compression since it typically results in smaller data sizes. (Explanation: Since Ryan's priority is how quickly these photos are sent, he wants to minimize the number of bits being transmitted.)

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? A. The image can no longer be represented using bits. B. The image will have been converted into an analog form. C. The image will require more pixels to display it on the screen. D. The image will require fewer bits in order to be represented.

D. The image will require fewer bits in order to be represented. (Explanation: No matter the method, compressing the image should reduce the number of bits needed to represent the image.)

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? A. Modifying a piece of open source software. B. Using open access research for which she does not acquire a license. C. Failing to publish her work under a Creative Commons license. D. Using images posted online by another student without permission or citation.

D. Using images posted online by another student without permission or citation. (Explanation: Since the other student's images are automatically protected under copyright law, Lucy must cite these images or make clear she has permission to use them in order to avoid legal consequences.)