Code.org Unit 1 test

Which of the following would result in a better digital approximation of an analog black and white image?

Decreasing the size of each sample square, thus increasing the number of samples taken.

what do more wires do

more wires the bigger the numbers you can store. each wire=1 bit.

Do we use unaltered digital information?

no its compressed example a 30 MB song can be compressed to 3 MB

bit

one digit in a binary code

what happens whenever you add a new bit

the amount of numbers one can make increases exponentially. In binary it doubles, in decimal it is times 10

higher quality sound and images

the more bits the higher quality the images and sound

how to sample a black and white image that is 4" x 6".

use a widget that would have 24 bits. depending on where I put the 1's and 0's the image will look different.

what can the 7-bit system code for?

128 characters. Symbols 0-31 and 127 were reserved for control characters (e.g. "Backspace" or "Delete") with the numbers 32-126 being used for printable characters.

You've been given a new cell phone with a 2 gigabyte data plan. You plan to use your phone for text messages, images, video, and music. Which of these categories are best compressed using lossless compression? Which of these categories are best compressed using lossy compression? Why?

"Images, video, and music are best compressed using lossy compression because you can lose data without the human eye or ear noticing much. Text messages can best be compressed using lossless compression because you can reduce the number of bits needed without losing any information. In a text, using abbreviations and symbols is ok because most people know what they mean. But if you are taking away, for example, all the vowels, which would be lossy compression, it will be harder to know what the message means."

What is the most important quality of lossless compression?

(D) The data is transformed to always make it smaller. It cannot always be re-constructed back to the original.

Which statement about analog and digital images is true?

(b) Sampling an analog image more frequently produces a digital image with a better representation.

"The binary pattern 01000001 represents the number 65 and?

01000001 does not only mean 65 because it can also mean A

In the 3-bit color system what is each color?

100=red, 010=green, 001=blue, 110=yellow, 011=cyan, 111=white, 000=black, 101=purple

What is the origin and use of the 7-bit system?

ASCII (American Standard Code for Information Interchange) system for character encoding. developed in 1963 as a 7-bit system allowing for 128 characters. Symbols 0-31 and 127 were reserved for control characters (e.g. "Backspace" or "Delete") with the numbers 32-126 being used for printable characters. As the 8-bit "byte" became standardized,

An author is preparing to send their book to a publisher as an email attachment. The file on their computer is 1000 bytes. When they attach the file to their email, it shows as 750 bytes. The author gets very upset because they are concerned that part of their book has been deleted by the email address. If you could talk to this author, how would you explain what is happening to their book?

If I could talk to the author I would simply explain that their book had gone through a process known as compression in which phrases that are repeated within the book are replaced with a symbol that allows the file to take up much less memory, but when someone opens the file to read his writing the words will appear the same as they did in the original document.

Number system

It is a system of naming and representing numbers. There are various types of numbers like Decimal number system (Base- 10), Binary number system (Base- 2), Octal number system (Base-8), and Hexadecimal number system (Base- 16).

what is lossless compression and what is it used with?

It is compression in which nothing is lost it can be decompressed back into the original thing

what is the smallest piece of information a computer can store and what can it do?

It's a bit and it can do yes or no questions?

How is a Creative Commons license different from a regular copyright?

It's a way to license out copyrighted work to those who follow the conditions of the person who owns the actual copyright so they can use it in their own work

Describe how the process of sampling, RGB pixels, and binary sequences work together to display a digital color image.

These two factors work together by first deciding whether a color is on or off with 0's and 1's, and then decide which color it is and by what degree the color shows with the order of 1's and 0's.

what is lossy compression and what things have this type of compression?

When it is compressed some of the info is thrown away this used on images

When using bits to represent fractions of a number, can you create all possible fractions?

Yes, you could use some bits to represent the numerator and some bits to represwent the denomerator Binary can represent some of the fractions of a number but not all of them

what does the 6-bit system allow one to do?

affect shade. 010000=dark red, 100000=red, 110000=bright red, concept works the same for the rest of the colors. ex: 001000=green

What happens to the odometer reading when a car drives beyond its maximum reading?

after they pass the cap they read zero and restart the count

similarities and differences between the binary and decimal systems?

both use zeros to show that there is nothing in a place, decimals counts from 1 to 10 binary 1 2 4 8 16 and so on, decimal uses bunch of numbers binary only 1's and 0's, and binary uses bits

Assume your friend just sent you 32 bits of pixel data (just the 0s and 1s for black and white pixels) that were encoded after sampling an image. Choose the two statements that are true.

c) The correct width and height must be input into the pixelation widget to produce the image. (d) The fact that only 32 bits were used to represent the image indicates relatively large sample squares were used. The digital image may vary from the analog image significantly.

Binary

it's a number system represented by 1's and 0's.

Why should we care about information being represented digitally? How does this impact you personally?

we should care about information being represented digitally because it allows users to acquire it with an ease that has never before been seen. However, this easy has influence our personalities as it has left us becoming more gullable as we believe everything that we read online and less patient as we are used to getting everything immediately.

pixilation widget

were you can code black and white pixels to make pictures. 1 makes the square white and 0 black. it can also be used to define width and height. (when it's white it means the light is on and when its black it means the light is off)