Download Quiz 1. Representing and Transmitting Information

AP Computer Science Principles
Name: _______________________________
Quiz 1. Representing and Transmitting Information
1. An online store uses 6-bit binary sequences to identify each unique item for sale. The store
plans to increase the number of items it sells and is considering using 7-bit sequences. Which
of the following best describes the result of using 7-bit sequences instead of 6-bit sequences?
A) 2 more items can be uniquely identified.
B) 10 more items can be uniquely identified.
C) 2 times as many items can be uniquely identified.
D) 10 times as many items can be uniquely identified.
2. A computer program uses 3 bits to represent integers. When the program adds the decimal
(base 10) numbers 5 and 3, the result is 0. Which of the following is the best explanation for
the result?
A) An overflow error occurred.
B) A round-off error occurred.
C) The result was affected by lossy data compression
D) The result was approximated by a floating-point representation
3. Which of the following is the best definition of a protocol?
A) A preliminary sketch of an idea
B) A set of rules governing the exchange or transmission of data between devices
C) The original draft of a diplomatic document
D) A physical system for sending binary information to another device
4. ASCII is a character-encoding scheme that uses 8 bits to represent each character. The
decimal (base 10) values 65 through 90 represent the capital letters A through Z, as shown in
the table below.
What ASCII character is represented by the binary (base 2) number 01001010 ?
A)
B)
C)
D)
H
I
J
K
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AP Computer Science Principles
5. You have a coordinate grid that is 25 x 25 units. Assuming that you encode the x and y
coordinate as separate numbers, what is the minimum number of bits that you will need to
encode a coordinate in that space?
A) 4
B) 14
C) 10
D) 5
6. The term "bit" stands for which of the following?
A) Binary Digit
B) Binary Information Technology
C) Basic Information Token
D) Binary Instruction
7. All digital data on your computer is ultimately stored using binary in some way.
A) True
B) False
8. ASCII has an encoding for every character of the alphabet as well as encodings for numbers
– that is, encodings for the symbols of the digits 0-9. So here is a trick question: How many
bits are required to store the text of the number "97" in ASCII?
A) 2 bits
B) 16 bits
C) 24 bits
D) 7 bits
9. Which of the following correctly pairs the bit sending technology with the underlying
system?
A) Copper Wire & Electric Voltage, Radio Wave & Beam of Light, Fiber Optic Cable &
Alternating Frequencies
B) Copper Wire & Beam of Light, Radio Wave & Electric Voltage, Fiber Optic Cable &
Alternating Frequencies
C) Copper Wire & Electric Voltage, Radio Wave & Alternating Frequencies, Fiber Optic
Cable & Beam of Light
D) Copper Wire & Beam of Light, Radio Wave & Electric Voltage, Fiber Optic Cable &
Alternating Frequencies
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AP Computer Science Principles
10. IP addresses are a way to identify devices connected to the internet (we'll learn more about
what IP addresses are soon!). An IPv4 address is encoded in 32 bits or 4 bytes. Typically
when you see an IP address it is organized as 4 separate numbers separated by periods, where
each of the 4 numbers is stored in 1 byte (8 bits). With this in mind, which of the following
would not be a possible IP address?
A) 8.8.8.8
B) 192.168.1.1
C) 32.344.216.42
D) 142.237.56.117
11. If it took you 2 minutes to download a 360 bit message, what was the bitrate of your
connection?
A) 180 bits / second
B) 3 bits / second
C) 1 bit / second
D) 720 bits / second
For the following questions, two of the suggested answers will be correct. For each of these
questions, you must select both correct choices to earn credit. No partial credit will be earned if
only one correct choice is selected.
12. Which of the following can be represented by a single binary digit?
Select two answers.
A)
B)
C)
D)
The position of a minute hand on a clock
The remainder when dividing a whole number by 2
The answer to a True or False question
The volume of a car radio
13. Suppose you receive a sequence of binary values that represent the purchase price for several
items. You want to determine the total cost by adding up all the purchase prices, however the
message you received was 12 bits and you can't remember whether the protocol uses a chunk
size of 3 or 4, so you decide to figure out what it would be in both cases. Given the following
binary sequence,
100110101111
which of the following are possible values for the total cost?
Select two answers.
A)
B)
C)
D)
34
255
28
22
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