Chapter 1: Digital Systems and Information

Question 1

How much Volt does an outlet usually use?

Answer 1

110V

Question 2

How much Volt does a computer usually use?

Answer 2

Up to 1.1V

Question 3

How much Volt does an iPhone usually use?

Answer 3

Up to 0.8V

Question 4

How many bits can a modern computer usually process at one time?

Answer 4

64 bit

Question 5

What does the CPU on a basic level when an user clicks on an image to show it on a device?

Answer 5

The CPU converts the digital info to analog and the device displays the analog image

Question 6

What is 11010 in decimal?

Answer 6

26

Question 7

Why is photo editing so taxing on a computer’s CPU?

Answer 7

Because the CPU is making lots of calculations because as the user changes the image, he/she changes the digital information of many pixels

Question 8

What is 110101.11 in decimal?

Answer 8

53.75

Question 9

What is an analog signal?

Answer 9

A signal that is continuous as opposed to having only discrete values

Question 10

What is a digital signal?

Answer 10

A signal that is not continuous across a range of values but that rather has only discrete values that it can take on

Question 11

What is a bit?

Answer 11

A binary digit (0 or 1)

Question 12

How do you convert a binary number to a decimal number?

Answer 12

By expanding the number into a power series with a base of 2

Question 13

In digital systems, we refer to 2 to the power of 10 as what?

Answer 13

K (kilo)

Question 14

In digital systems, we refer to 2 to the power of 20 as what?

Answer 14

M (mega)

Question 15

In digital systems, we refer to 2 to the power of 30 as what?

Answer 15

G (giga)

Question 16

In digital systems, we refer to 2 to the power of 40 as what?

Answer 16

T (tera)

Question 17

Conventionally people use a kilobit to represent 1000 bits but in reality it is how many bits?

Answer 17

It is actually 2 to the power of 10, which is 1,024 bits

Question 18

How do you convert a decimal number to a binary number?

Answer 18

By successively dividing by 2 and noting down the remainders. Then, you read the remainders from bottom to top to get the binary number.

Question 19

The octal number system has which digits?

Answer 19

The digits 0 through 7

Question 20

How do you convert an octal number to a decimal number?

Answer 20

By expanding the number into a power series with a base of 8

Question 21

The hexadecimal number system has which digits?

Answer 21

Digits 0 to 9 and A, B, C, D, E, F

Question 22

How do you convert a hexadecimal number to decimal?

Answer 22

By expanding the number in a power series with a base of 16

Question 23

How do you convert a binary number to an octal number?

Answer 23

By separating the binary number into groups of three bits each, starting from the decimal point and proceeding to the left and right. Then, you convert each of those triplets into the corresponding number.

Question 24

How do you convert a binary number to a hexadecimal number?

Answer 24

By separating the binary number into groups of four bits each, starting from the decimal point and proceeding to the left and right. Then, you convert each of those groups of four into the corresponding number.

Question 25

How do you convert an octal or hexadecimal number to a binary number?

Answer 25

By converting each octal (or hexadecimal) digit to a 3-bit (4-bit) binary equivalent and deleting extra 0s.

Question 26

What's the sum of 01100 and 10001?

Answer 26

11101

Question 27

What's the sum of 10110 and 10111?

Answer 27

101101

Question 28

What's 10110 minus 10010?

Answer 28

00100

Question 29

What's 10110 minus 10011?

Answer 29

00011

Question 30

What is 1011 times 101?

Answer 30

110111

Question 31

What number system did computers before the early 90s use?

Answer 31

Hexadecimal

Question 32

How do you convert a decimal number to an octal number?

Answer 32

You successively divide by 8 and note down the remainders. Then, you read the remainders from bottom to top to obtain the octal number.

Question 33

What does LSB stand for?

Answer 33

Least significant bit

Question 34

What does MSB stand for?

Answer 34

Most significant bit

Question 35

What's the sum of 59F and E46?

Answer 35

13E5

Question 36

What's the product of 762 and 45 (both are octal numbers)?

Answer 36

43772

Question 37

How do you convert decimal fractions to binary?

Answer 37

You successively multiply by 2 and note down the integer parts. Then, you read the integer parts from top to bottom to obtain the binary fraction.

Question 38

How do you convert decimal fractions to octal?

Answer 38

You successively multiply by 8 and note down the integer parts. Then, you read the integer parts from top to bottom to obtain the binary fraction.

Question 39

What does BCD stand for?

Answer 39

Binary-coded decimal

Question 40

What is an advantage and a disadvantage of using BCDs in computers over regular binary numbers?

Answer 40

+: Conversion from decimal to BCD and back is faster -: BCDs need more bits than its equivalent binary number, which means higher manufacturing costs and more power

Question 41

What is 185 in BCD?

Answer 41

0001 1000 0101

Question 42

How do you convert a decimal number to BCD?

Answer 42

For every digit in the decimal number you just use a group of 4 bits to represent each of these digits

Question 43

The standard binary code for the alphanumeric characters is called what?

Answer 43

American Standard Code for Information Interchange (ASCII)

Question 44

Why do we use parity bits?

Answer 44

To detect errors in data communication and processing

Question 45

What is a parity bit?

Answer 45

It is an extra bit that is added to a number to make the total number of 1s either even (even parity) or odd (odd parity)

Question 46

What is even parity?

Answer 46

Adding an extra parity bit to a number to make the number of 1s even

Question 47

What is odd parity?

Answer 47

Adding an extra parity bit to a number to make the number of 1s odd

Question 48

In the case of even parity, how do we figure out that there was an error?

Answer 48

If we get a binary number with an odd number of 1s, then a bit (or an odd number of bits) contained an error

Question 49

In the case of odd parity, how do we figure out that there was an error?

Answer 49

If we get a binary number with an even number of 1s, then a bit (or an odd number of bits) contained an error

Question 50

What is Gray code?

Answer 50

It is a binary code, where the number of bit changes from one number to the next is always 1 (as opposed to a varied number in the regular binary code)

Question 51

Mention the numbers 0 to 7 in a 3-bit Gray code

Answer 51

000 001 011 010 110 111 101 100