CSC103 Homework Assignment 1 Solution

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Each problem was given 2 points.

Problem 1:

100100

100000

Problem 2:

0
1
2
10
11
12
20
21 
22
100
101
110
111
112
120
121
...

Problem 3:

2110

10000

Problem 4:

The keyword here was "multiplied by 2." The computer deals with bits. A bit can be on or off. 1 or 0. Two states. If you get 2 bits, they can be in 4 states: 00, 01, 10, or 11. If we add another bit, the number of possibilities doubles: 000, 001, 010, 011, 100, 101, 110, 111. From 8 we go to 16, to 32, to 64, to 128, 256, 512, 1024, 2048, etc...

This relationship also exists with memory sticks. We can get 128MB sticks, 256 MB sticks, 512 MG sticks, 1GB sticks, 2GB sticks, 4 GB sticks and so on.

Problem 5:

The main good characteristics we find in electricity:

• It's cheap
• It travels fast, almost at the speed of light
• It requires only metal wires, and they can be fairly small
• We can switch it on and off with little effort. The transistor is almost perfect to switch it on/off.

For the math problem, you had to show how you came up with your result. Also, many of you used miles and kilometers in the same equation without changing the units (that's bad!), or assumed the wire was going through the earth. The distance is 1/2 the circumference of the earth, not 1/2 the diameter!

• The speed of light is 300,000 km/s
• The circumference of the earth is 40,000 km.
• Divide 1/2 circumference by the speed of light: 20,000/ 300,000 and you get 1/15 or 0.06 sec. It takes electricity about 6 hundredth of a second to go half way around the globe. That's fast!