Digital and analog

Question 1

Analog

Answer 1

Analog transmission and storage of information involve making an exact copy of the original information in a new medium.

Question 2

Examples of analog

Answer 2

• Painting medium 1: persons face medium 2: canvas
• AM and FM radio
• Printing press

Question 3

Digital

Answer 3

Digital transmission and storage of information involve converting information first into numbers, then sending or storing it.

Question 4

Samples

Answer 4

1. Analog technology copies the whole wave and all of the original information
2. Digital technology converts certain points of the original information, called samples, so some information is always lost.

Question 5

Samples-analog-advantage

Answer 5

Copies the whole wave, information isn’t lost

Question 6

Samples-analog-disadvantage

Answer 6

Size cannot be made smaller by sampling.

Question 7

Samples-digital-advantage

Answer 7

Size can be made smaller by sampling

Question 8

Samples-digital-disadvantage

Answer 8

Copies only parts of waves

Question 9

Noise

Answer 9

Anytime information is copied from one form to another, errors appear. This is called noise.

Question 10

Analog and noise

Answer 10

1. Analog tries to copy all information exactly.
2. Since all copies have some noise, this mean’s making a copy of an analog copy will also copy the noise.
3. Therefore, every time you make an analog copy, you also copy the noise.

Question 11

Digital and noise

Answer 11

1. Digital signals also have noise, but they are converted to numbers, which don’t have noise.
2. When there is only a small amount of noise, digital signals do not lose any information (it’s perfect)
3. When there is a large amount of noise, digital signals can be completely lost.

Question 12

Noise-digital-advantage

Answer 12

If small amount of noise, copy is perfect.

Question 13

Noise-digital-disadvantage

Answer 13

If large amount of noise, copy loses all information.

Question 14

Noise-analog-advantage

Answer 14

If small amount of noise, copy is poor but understandable

Question 15

Noise-analog-disadvantage

Answer 15

Noise builds on noise when copies are made of copies

Question 16

Compression

Answer 16

1. Digital signals can be compressed or shrunk so that they take up less space
2. Compressed information is easier to store and is quicker to transmit

Question 17

Compression and analog

Answer 17

Analog signals cannot be easily compressed.

Question 18

Lossy compression

Answer 18

In lossy compression, information is lost, but the size of the file can be shrunk by a lot.

Question 19

Lossless compression

Answer 19

In lossless compression there is no change in the numbers, so no quality is lost, but there is only a small change in the size of the file.

Question 20

Digital-compression- advantages

Answer 20

Digital signals can be compressed saving space.

Question 21

Digital-compression- disadvantages

Answer 21

if compression is lossy, quality suffers

Question 22

Analog-compression- advantages

Answer 22

N/A

Question 23

Analog-compression- disadvantages

Answer 23

Analog signals are difficult to compress.

Question 24

Copying analog vs digital

Answer 24

1. Digital signals are easy to copy since they are made of numbers.
2. analog signals are harder to copy since they are stored on physical media.

Question 25

Copying-analog-advantages

Answer 25

must be physically present to steal, easy to keep private.

Question 26

Copying-analog-disadvantages

Answer 26

Hard to "back up" information or share it with others.

Question 27

Copying-digital-advantages

Answer 27

Easily moved and easily stored

Question 28

Copying-digital-disadvantages

Answer 28

Easily stolen and can be hacked

Question 29

Encryption

Answer 29

Digital data can be put into code so that they can be kept private. Analog data is very difficult to encrypt and can be harder to keep private.

Question 30

Loss of quality with use analog and digital

Answer 30

Machines have to touch the physical media when accessing analog information, this damages the media and makes it lower quality after many uses. Accessing digital information is just reading numbers, so digital information does not lose quality after use.

Question 31

Storage-digital-advantages

Answer 31

All types can be stored and sent on computers

Question 32

Storage-digital-disadvantages

Answer 32

Requires expensive and complex computers

Question 33

Storage-analog-advantages

Answer 33

Storage machines are simpler and cheaper

Question 34

Storage-analog-disadvantages

Answer 34

Each type of analog needs a special piece of equipment.

Question 35

Number of signals

Answer 35

Many digital signals can be sent at once. It is hard to send many analog signals at the same time.

Question 36

Reversible reaction

Answer 36

1. In a reversible reaction, a chemical equation can go in both directions. 2. Left-side substances can react to form the right-side substances 3. Right-side substances can react to form the left-side substances.

Question 37

Equilibrium

Answer 37

1. A reversible reaction is at equilibrium if the reaction rate to the right is the same as the reaction rate to the left. 2. When a reaction has reached equilibrium, the concentrations of all substances don't change, even though the reaction doesn't stop.

Question 38

Conditions and equilibrium

Answer 38

1. reversible reactions only stay at equilibrium when the conditions stay the same. 2. If you change the conditions, the reaction will no longer be at equilibrium 3. The reaction will now have a higher reaction rate either to the right or to the left until a new equilibrium is reached and the reaction rates in both directions are equal again.

Question 39

Three conditions that affect equilibrium

Answer 39

1. Concentration 2. Pressure 3. Temperature

Question 40

Le Chatelier's principle

Answer 40

If a chemical system at equilibrium experiences a change in concentration, temperature, or pressure, then the equilibrium shifts to counteract (or undo) the change, and a new equilibrium is reached.

Question 41

Endo and exothermic reversible reactions

Answer 41

A reversible reaction that is endothermic when going to the left must be exothermic when going to the right.

Question 42

Pressure and Equilibrium

Answer 42

Pressure effects the equilibrium of a reversible reaction only if all the substances involved are gases.

Question 43

Pressure

Answer 43

Gas pressure is cause by the force of gas particles hitting the wall of a container. If more particles hit the wall of the container, the pressure is higher.

Question 44

Pressure and Le Chatelier's principle

Answer 44

Shifting toward the side of the equation that has more particles increases the pressure.