AP CS Principles Semester 1 Review

The ASCII (American Standard Code for Information Interchange) is a character encoding scheme that translates characters into numbers and can be used with either decimal or hexadecimal numbers. A portion of the table, with

• 51

• 81

• 113

• 71

Sara is a network engineer for a large social media organization, and has been tasked by her lead engineer to partition part of the network into subnets. In order to do this, Sara must do some binary arithmetic using a subnet mask with an IP of 255.255.255.192

Which of the following sequences are equivalent to the binary values for each octet of this subnet mask IP address?

• 11111111.11111111.11111111.11000000

• 11111111.11111111.11111111.11000001

• 00000000.00000000.00000000.00111111

• FF-FF-FF-C0

For the purposes of this question, focus on the representations themselves (color, ASCII, hexadecimal, binary) rather than the data. Ignore the fact that PURPLE is not equivalent to the other representations.

• binary to ASCII

• hexadecimal to color

• color to binary

• binary to color

Which of the following can be represented by exactly two binary digits?

Select TWO answers

• Compass directions (North, South, East, and West).

• Classifying a student by whether or not they are passing and whether or not they have perfect attendance.

• The first letter of someone's last name

• A person's height.

Consider the following statement.

"There are 10 types of people in this world: Those who understand binary, and those who don't."

Why might computer scientists find this statement humorous?

• There are ten types of computer programmers in the world

• 10 (binary) = 2 (decimal)

• 10 (decimal) = 1010 (binary)

• 10 (hexadecimal) = 16 (decimal) = 10000 (binary)

Those that post videos on YouTube are offered a host of different statistics to help them understand their viewers. This data can be looked at as values or graphs to understand the quantity of users or the categorical information like the location or device type.

Which of the following is the best reason a creator would want to know this data?

• Compare their statistics against rivals

• Device usage may affect the design elements of the video

• Time data is indicative of demographics

• Device usage is indicative of demographics

Internet users need to be able to transfer private data online, like credit card numbers and social security numbers. Some cryptographic algorithms help ensure this safety.

What makes cryptographic algorithms secure?

• The algorithms used for cryptography are based on intractable problems, making them extremely difficult to break.

• The algorithms used for cryptography have been used for such a long time that we know they are very secure.

• The algorithms used for cryptography are solvable, but the solutions are kept under a secure government protection service.

• The algorithms used for cryptography are a secret.