AP CSP Chapter 1 Review

What is the best explanation for why digital data is represented in computers in binary?

• The binary number system is the only system flexible enough to allow for representing data other than numbers.
• As a consequence of history, early pioneers of computing were making secret codes in binary, and this simply evolved into modern computing.
• it's impossible to build a computing machine that uses anything but binary to represent numbers
• It's easier, cheaper, and more reliable to build machines and devices that only have to distinguish between binary states.

What is the 4 bit number for the decimal number Ten(10)?

• 0010
• 1010
• 0110
• 0101

What is the minimum number of bits you would need to encode the 26 letters of the alphabet plus a space - a total of 27 characters?  

• 2 bits
• 3 bits
• 5 bits
• 6 bits

Number bases, including binary, decimal, and hexadecimal, are used to view and represent digital data. Which of the following is NOT true about representing digital data?

• At one of the lowest levels of abstraction, all digital data can be represented in binary using only combinations of the digits zero and one.
• Hexadecimal is used to represent digital data because hexadecimal representation uses only 1 digit to represent groups of 4 binary digits
• Binary can be used to represent more complex, higher level abstractions, including but not limited to numbers, characters, and colors.
• There is a limit to the number of things that can be represented in binary data at which point switching to hexadecimal representation is necessary.

Consider the following numbers given in Binary (BIN), Decimal (DEC), and Hexadecimal (HEX) representations:
 BIN: 1110
DEC: 13
HEX: F

• BIN: 110, DEC 13, HEX: F
• DEC: 13, BIN: 1110, HEX: F
• DEC: 13, HEX: F, BIN: 1110
• HEX: F, DEC: 13, BIN: 1110

A middle school is expanding to open a high school next year, doubling the total number of students. The school keeps a database in which each student's unique ID number is stored as an 8 bit number called studentID. Before the arrival of the new students almost every 8 bit number has already been assigned to a student. Which is the most accurate description of how the school could modify the way studentID is represented in the database to ensure each incoming student receives a unique ID?  

• Add a bit to studentID to double the number of IDs that the database can represent.
• Double the number of bits in studentID to double the number of IDs that the database can represent.
• Keep using and 8-bit number for studentID but reserve the first bit to indicate middle school or high school.
• Remove a bit from studentID to make room for incoming students

A user clicks on a website, and it begins to load immediately, but it takes a long time to load completely and pictures appear slowly, one by one. Which of the following is demonstrated through this situation?

• High bandwidth, high latency
• Low bandwidth, high latency
• High bandwidth, low latency
• Low bandwidth, low latency

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

ASCII is a character-encoding scheme that uses a numeric value to represent each character. For example, the uppercase letter "G" is represented by the decimal (base 10) value 71. A partial list of characters and their corresponding ASCII values are shown in the table below.

• A
• L
• V
• Y

A video-streaming Web site uses 32-bit integers to count the number of times each video has been played. In anticipation of some videos being played more times than can be represented with 32 bits, the Web site is planning to change to 64-bit integers for the counter. Which of the following best describes the result of using 64-bit integers instead of 32-bit integers?

• 2 times as many values can be represented.
• 32 times as many values can be represented
• 2^32 times as many values can be represented.
• 32^2 times as many values can be represented.