UNIT 1- DIGITAL INFO

What is the minimum numbers of bits you would need to encode all uppercase and lowercase letters of the English alphabet?

What is the minimum numbers of bits you would need to encode all uppercase and lowercase letters of the English alphabet?

6 (52 overall letters, 6 bits equals 52 exactly)

A program uses 4 bits to store numbers.  When it adds 10 and 7, the result is 1.  Which of the following best explains why?

an overflow error led the program to reset to 0 at the number 16 (4 bits equals 15 and 10+7= 17 which is more than 15 so it causes overflow)

Which binary # is the greatest?

11001

11000

11100

11011

11010

11100 (why? more ones on the left hand side of the binary means greater, so 11000 is the greatest binary)

The Pokedex currently includes 893 unique Pokemon.  If each Pokemon were provided a unique ID number, what would be the minimum number of bits required?

10 (the 10 bit number that equals exactly 893 is 110111101)

Why is binary used to encode information?

The difference between 2 states (A or B) is the clearest, most accurate way to send messages.

If you wrote a program that uses only 4 bits to represent decimal numbers (0, 1, 2, 3, etc.), what is the SMALLEST number for which an overflow error would occur?

16 (4 bits equals 15 so any #>15 will cause overflow and the number after 15 is 16 so thats the smallest that will cause it to reset/overflow)

For each additional bit in a binary sequence, what happens to the amount of numbers we can make?

it doubles (ex: 4 bits is 0000 turned off and on is 11111, the number made from adding all 1s is 15 because the farthest righthand 1 equals 1 in decimal then the next 1 is multiplied by 1 times 2, then the next by 2 times 2, and the last/farthest lefthand 1 by 4 times 2)

Which of the following is an 8-bit system for English character encoding?

ASCII

If someone told you that 97 101 98 was ASCII for "CHS", you could know immediately that this isn't true.  Which is the best explanation?

the letters C, H and S are more spread out in the alphabet than the numbers 97, 98 and 101

binary digits

0s (off) and 1s (on) used to represent digital data

The number 30 in binary is

11110

The smallest piece of information stored or transmitted, usually the difference between two states (A or B, or 0 or 1), is known as a __________.

bit

A program adds 2 numbers and an overflow error results.  Which of the following is the most likely reason?

the calculated sum is greater than the amount of memory set aside to store it

Convert this binary number to decimal (base-10): 11110111

247

The number 9 in binary is

1001

Does binary 01000001 always represent the capital letter A?

No, that is simply what it represents in ASCII, which is based on English.  01000001 may represent other characters in codes for other languages. (what something represents in one language is very likely going to be different from its equivalent in a different language)

Your friend is a fabulous poet.  She handwrites all of her poems.  When she writes a poem for you, you use your smarthphone to take a photo of it and post it online.  Which of these statements is true?

the photo is a digital representation of the analog poem (photos are digitized while poems are natural/analog)

List these hexadecimal RGB colors, in this order:

FFF, F00, 0F0, 00F, 000

white, red, green, blue, black

(FFF is pure and 000 is also pure so they are white and black respectively, red is similar to white so it has F as the farthest left value, green is in the middle of red and blue so it has F in the middle and blue is 00F because its similar to black so its F is the farthest right value)

24-bit RGB uses...

1 byte for each color channel (r, g, or b to keep it simple)

List the hexadecimal RGB codes for the colors numbered above, in order from 1 to 3:

F0F, FF0, 0FF

Which is 12-bit RGB for cyan?

00ffff

If your friend sent you 64 bits of pixel data (just the 0s and 1s for black and white pixels) that were encoded after sampling an image, which of the following must be true?

The correct width and height must be included in order to produce the image.

1. converting hexadecimal to decimal:

2. converting decimal to hexadecimal:

1. multiply the tens place by 16 and add the ones place

2. divide the decimal by 16 and if there is a remainder, multiply the remainder by 16

1 to A is…

1 to 10

1=1, 2=2, 3=3, 4=4, 5=5, 6=6, 7=7, 8=8, 9=9, A=10

A to F is…

10 to 16

A = 10, B=11, C=12, D=13, E=14, and F=15

the base for regular numbers is blank, the base for binary numbers is blank, the base for hexadecimal numbers is blank

10, 2, 16, respectively

converting hexadecimal to decimal: E5 is…

(14*16) + 5 = 229

E=14 and multiply it by 16 because thats the base then add the ones value which is 5 to get the final conversion.

The decimal (regular) number 250 is what in hexadecimal?

FA (250/16=15 remainder .625; multiply .625 by 16 =10; F in hex is equal to 15 and A is 10 so the hexadecimal version of decimal 250 is FA; going from hexadecimal to decimal, F multiplied by 16 is 240 and adding A being 10 equals 250)

The hexadecimal number 25 is what in decimal (regular) numbers?

37 (2 times 16 = 32 + 5 = 37)

Which is 12-bit RGB for cyan?

00ffff

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

Decrease the size of each sample square, thus increasing the number of samples taken. (more squares means more detailed digital version of the analog)

What is overflow why does it occur?

overflow is when a computer doesn’t have enough memory or storage space to account for the values you are storing, so it resets to zero.