APCSP Practice Test
What is the best explanation for digital data is represented in computers in binary?
A. The binary number system is the only number system flexible enough to allow for representing data other than numbers.
B. As a consequence of history: early pioneers of computing were making secret codes in binary, and this
simply evolved into modern computing.
C. It's impossible to build a computer machine that uses anything but binary to represent numbers.
D. It's easier, cheaper, and more reliable to build machines and devices that only have to distinguish between binary states. - correct answerD. 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)?
A. 0010
B. 1010
C. 0110
D. 0101 - correct answerB. 1010
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?
A. 2 bits
B. 3 bits
C. 5 bits
D. 6 bits - correct answerC. 5 bits
The next questions refers to the hexidecimal (base 16) number system: 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?
A. 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.
B. Hexadecimal is used to represent digital data because hexadecimal representation uses only 1 digit to represent groups of 4 binary digits.
C. Binary can be used to represent more complex, higher level abstractions, including but not limited to numbers, characters, and colors. D. 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. - correct answerD. 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
Which of the following lists the numbers in order from least to greatest?
A. BIN: 1110, DEC: 13, HEX: F
B. DEC: 13, BIN: 1110, HEX: F
C. DEC: 13, HEX: F, BIN: 1110
D. HEX: F, DEC: 13, BIN: 1110 - correct answerB. DEC: 13, BIN: 1110, HEX: F
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?
A. Add a bit to studentID to double the number of IDs that the database can represent.
B. Double the number of bits in studentID to double the number of IDs that the databases can represent. C. Keep using an 8-bit number for studentID but reserve the first bit to indicate middle school or high school.
D. Remove a bit from studentID to make room for incoming students. - correct answerA. Add a bit to studentID to double the number of IDs that the database can represent.
NOTE: Doubling the number of bits would obviously make room for more student IDs, but it's inaccurate to say that that doubles the number of possible IDs. If the number of bits went from 8 to 16, it's 256 TIMES AS MANY possible ids. 8 bits = 256 values and 16 bits = 65,536 IDs.
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?
A. High bandwidth, high latency
B. Low bandwidth, high latency
C. High bandwidth, low latency
D. Low bandwidth, low latency - correct answerD. 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?
A. 9 bits
B. 10 bits
C. 16 bits
D. 17 bits - correct answerA. 9 bits The next question refers to hexadecimal which is a base-16 number system - a number system that uses one of 16 possible digits for each place value.
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.
Decimal ASCII
80 P
81 Q
82 R
83 S
84 T
85 U
86 V
87 W
88 X
89 Y
90 Z
A. A
B. L
C. V
D. Y - correct answerC. V
NOTE: In order to calculate the value of the base-16 number 56, it is 5*16^1 + 6*16^0 = 86, which maps to 'V' in the table
What is the best explanation for digital data is represented in computers in binary?
A. The binary number system is the only number system flexible enough to allow for representing data other than numbers.
B. As a consequence of history: early pioneers of computing were making secret codes in binary, and this
simply evolved into modern computing.
C. It's impossible to build a computer machine that uses anything but binary to represent numbers.
D. It's easier, cheaper, and more reliable to build machines and devices that only have to distinguish between binary states. - correct answerD. 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)?
A. 0010
B. 1010
C. 0110
D. 0101 - correct answerB. 1010
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?
A. 2 bits
B. 3 bits
C. 5 bits
D. 6 bits - correct answerC. 5 bits
The next questions refers to the hexidecimal (base 16) number system: 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?
A. 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.
B. Hexadecimal is used to represent digital data because hexadecimal representation uses only 1 digit to represent groups of 4 binary digits.
C. Binary can be used to represent more complex, higher level abstractions, including but not limited to numbers, characters, and colors. D. 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. - correct answerD. 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
Which of the following lists the numbers in order from least to greatest?
A. BIN: 1110, DEC: 13, HEX: F
B. DEC: 13, BIN: 1110, HEX: F
C. DEC: 13, HEX: F, BIN: 1110
D. HEX: F, DEC: 13, BIN: 1110 - correct answerB. DEC: 13, BIN: 1110, HEX: F
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?
A. Add a bit to studentID to double the number of IDs that the database can represent.
B. Double the number of bits in studentID to double the number of IDs that the databases can represent. C. Keep using an 8-bit number for studentID but reserve the first bit to indicate middle school or high school.
D. Remove a bit from studentID to make room for incoming students. - correct answerA. Add a bit to studentID to double the number of IDs that the database can represent.
NOTE: Doubling the number of bits would obviously make room for more student IDs, but it's inaccurate to say that that doubles the number of possible IDs. If the number of bits went from 8 to 16, it's 256 TIMES AS MANY possible ids. 8 bits = 256 values and 16 bits = 65,536 IDs.
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?
A. High bandwidth, high latency
B. Low bandwidth, high latency
C. High bandwidth, low latency
D. Low bandwidth, low latency - correct answerD. 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?
A. 9 bits
B. 10 bits
C. 16 bits
D. 17 bits - correct answerA. 9 bits The next question refers to hexadecimal which is a base-16 number system - a number system that uses one of 16 possible digits for each place value.
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.
Decimal ASCII
80 P
81 Q
82 R
83 S
84 T
85 U
86 V
87 W
88 X
89 Y
90 Z
A. A
B. L
C. V
D. Y - correct answerC. V
NOTE: In order to calculate the value of the base-16 number 56, it is 5*16^1 + 6*16^0 = 86, which maps to 'V' in the table
