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WorksheetsComputer Science Principles
Total questions: 62
Worksheet time: 47mins
Which of the following decimal (base-10) values is equivalent to the binary (base-2) value 101001?
22
37
41
82
The smallest unit of information is
a byte (Pronounced: bite)
a bit
a nibble
a block
Fortran
The smallest visual element on a video monitor is called what?
Character
Pixel
Byte
Kwerk
According to Moore’s Law, increases in technological performance should approximately double every year? If this holds true, how much can performance be expected to increase over 5 years?
10 times as much
100 times as much
32 times as much
16 times as much
What is the decimal equivalent of 11010011?
211
210
209
208
The resulting image will be a grayscale version of the original image.
The overall brightness of all pixels in the resulting image will be darkened.
The resulting image will be completely white.
All of the colors of the resulting image will be inverted, like a negative, of the
original image.
A student is recording a song on her computer. When the recording is finished, she saves a copy on her computer. The student notices that the saved copy is of lower sound quality than the original recording. Which of the following could be a possible explanation for the difference in sound quality?
The song was saved using fewer bits per second than the original song.
The song was saved using more bits per second than the original song.
The song was saved using a lossless compression technique.
Some information is lost every time a file is saved from one location on a computer to another location.
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 binary sequences. Which of the following best describes the
result of using 7-bit sequences instead of 6-bit sequences?
10 more items can be uniquely identified.
2 more items can be uniquely identified.
2 times as many items can be uniquely identified.
10 times as many items can be uniquely identified.
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? ( Hint: write as a binary number. How many bits? )
An overflow error occurred.
A round-off error occurred.
The result was affected by lossy data compression.
The result was approximated by a floating-point representation.
Digital images are often represented by the red, green, and blue values (an RGB triplet) of each individual pixel in
the image. A photographer is manipulating a digital image and overwriting the original image. Which of the
following describes a lossless transformation of the digital image?
Compressing the image in a way that may lose information but will suffer only a small loss of image quality.
Creating the gray scale of an image by averaging the amounts of red, green, and blue in each pixel and
assigning this new value to the corresponding pixel in the new image. The new value of each pixel represents
a shade of gray, ranging from white to black.
Creating the negative of an image by creating a new RGB triplet for each pixel in which each value is calculated by subtracting the original value from 255. The negative of an image is reversed from the original; light areas appear dark, and colors are reversed.
Modifying part of the image by taking the pixels in one part of the picture and copying them to the pixels in
another part of the picture.
What is 23 in binary
10101
10110
10111
11000
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 image below shows an encoding for a black and white pixel image. The first two bytes of the data (circled in red) are used to encode the width and height of the image.
What is the best term for this type of "data about the data"?
Megadata
Superdata
Metadata
Predata
The next two questions use a robot in a grid of squares. The robot is represented as a triangle, which is initially facing up, towards the top of the grid. The robot is moved according to the instructions in the chart above.
Consider the following program which uses commands from the pseudocode described above.
REPEAT 4 TIMES {
MOVE_FORWARD()
MOVE_FORWARD()
MOVE_FORWARD()
ROTATE_RIGHT()
MOVE_FORWARD()
ROTATE_RIGHT()
MOVE_FORWARD()
ROTATE_RIGHT()
}
Which of the following images shows the path and ending location of the robot that will result from executing the code above. The starting location of the robot is shown as dotted triangle for cases where the robot does not start and end at the same location.
00110011 + 01000110
2. which is file format for video?
Motion Picture Expert Group (MPEG)
Flash (flv)
Wave format (WAV)
JAVA
Number systems with different bases such as binary (base-2) and decimal (base-10) are all 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.
The same value (number) can have a different representation depending on the number system used to represent it.
Groups of bits can be used to represent abstractions, including but not limited to numbers and characters.
Some large numbers cannot be represented in binary and can only be represented in decimal.
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. Of the options provided below, which is the smallest change to the way studentID is represented necessary 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 an 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
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
Two students have developed a protocol in which they send 4-bit messages to each other. They decide to modify their protocol to start sending 8-bit messages instead. How many more values can be represented in an 8-bit message than a 4-bit message?
21 = 2 times as many values
22= 4 times as many values
23 = 8 times as many values
24 = 16 times as many values
Which of the following is a true statement about 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 state.
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 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.
An artist makes an RGB raster image in which each pixel color is encoded with 12-bits --- 4 bits each for red, green and blue.
Which of the following correctly shows the hexadecimal value for Red as a 12-bit representation.
F00
00F
FF00
FF0000
A compression scheme for long strings of bits called run-length encoding is described as follows:
Rather than record each 0 and 1 individually, instead record "runs" of bits by storing the number of consecutive 1s and 0s that appear.
Since it's binary, any run of 0s must be followed by a run of 1s (even if the run is only 1-bit long) and vice versa. Thus, you can store a list of small numbers that represents the alternating runs of 0s and 1s. The image above is an example:
To uncompress the data back into its original binary state, you simply reverse the process. This technique is an example of what type of compression?
Lossy compression
Lossless compression
Fast Fourier Transform compression
Tailored compression
Consider the following incorrect program, which is intended to move the robot around the perimeter of a grid, as indicated by the drawing above. The starting position and direction of the robot is indicated in the diagram.
Line 1: REPEAT 4 TIMES
Line 2: {
Line 3: MOVE_FORWARD()
Line 4: ROTATE_RIGHT()
Line 5: MOVE_FORWARD()
Line 6: MOVE_FORWARD()
Line 7: MOVE_FORWARD()
Line 8: MOVE_FORWARD()
Line 9: ROTATE_RIGHT()
Line 10: }
Given the options below, which lines should be removed so the program will work as intended?
Line 3 and Line 4
Lines 5, 6, 7, 8 and 9
Line 8 and Line 9
Line 9
What are the benefits of text compression?
two answer
Save computer space
count binary number
to restart
Transfer data faster
