AP CSP Unit 2 Assessment

Approximately how much bigger (how many more bytes) is a megabyte than a kilobyte?

• 100,000 times bigger

• 1,000 times bigger

• 1,000,000,000 times bigger

• 1,000,000 times bigger

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

The colors of the pixels in a digital image are often represented by red, green, and blue values between 0 and 255 (an RGB triplet).

A photographer is manipulating a digital image to lighten it because all of the RGB values in the image are less than 100, making it very dark.

He does this by adding 20 to the R, G, and B values of each pixel, then overwriting the original image. What type of transformation is the photographer using on the digital image?

• Lossless transformation

• Lossy transformation

• Multiband transformation

• Chrome Sampling transformation

There are 240 different values that can be represented by one Green component of a pixel?

• True

• False

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

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

• When the problem can be solved in a reasonable time and an approximate solution is acceptable.

• When the problem can be solved in a reasonable time and an exact solution is needed.

• When the problem cannot be solved in a reasonable time and an exact solution is needed.

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

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.

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

• Sending a compressed version of a file ensures that the contents of the file cannot be intercepted by an unauthorized user.

Approximately how much bigger (how many more bytes) is a megabyte than a kilobyte?

• 100,000 times bigger

• 1,000 times bigger

• 1,000,000 times bigger

• 1,000,000,000 times bigger