AP Computer Science Test - Unit 2

Which of the following programs is most likely to benefit from the use of a heuristic?

A program that finds the shortest driving route between two locations on a map

Digital images are often represented by the red, green, and blue values 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?

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.

Why are there so many different formats for representing the same kind of information?

Each type of format can only compress the file in one way. For example, PNG can only compress a file using lossless. This means that every file format compressor does its own way of compressing because there are so many files that need to be compressed differently.

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

Select the answer that lists the units of bytes in ascending order (from smallest to largest)

Kilobyte, gigabyte, terabyte

The colors of the pixels in a digital image are often..... What type of transformation is the photographer using on the digital image?

Lossless transformation

A raw digital sound file samples a sound wave at some interval... This technique is an example of what type of compression?

Lossy compression

Describe the difference between lossy + lossless compression. Give examples of each.

Lossy: JPEG Lossless: PNG

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 the reason for a change in sound quality?

The song was saved using fewer bits per second than the original song.

Which of the following is a true statement about data compression?

There are trade-offs involved in choosing a compression technique for storing and transmitting data

Under which of the following conditions is it most beneficial to use a heuristic approach to solve a problem?

When the problem cannot be solved in a reasonable time and an approximate solution is acceptable

A video-streaming web site uses 32-bit integers to count the number of times each video has been played, in anticipation.... Which of the following best describes the result of using 64-bit integers instead of 32-bit integers?

2^32 times as many values can be represented