APCSP - Unit 1 Review

Front

Here are three 4-bit binary numbers: 0010, 1010, and 0110. Which Base 10/decimal numbers is not equal to one of these?

Back

9

Answer explanation

0010 -> 2

1010 -> 10

0110 -> 6

Remember, all binary numbers that end in 0 are even. All binary numbers that end in 1 are odd.

Front

What is the minimum number of bits required to assign a unique value to 50 different things?

Back

6

Answer explanation

Max 4 bit number is 15.

Max 5 bit number is 31.

Max 6 bit number is 63.

Max 7 bit number is 121.

Since we are looking for the MINIMUM number of bits required, the correct answer is 6.

Front

Why does representing certain numbers (like irrational numbers or repeating decimals) cause loss of precision in binary?

Back

A fixed number of bits causes round-off errors.

Answer explanation

While it is true that a fixed number of bits can cause overflow errors, when we are talking specifically about loss of precision, that concerns round-of errors since you can't represent all fractional numbers using a fixed number of bits.

Front

Moving from using 2 bits to 8 bits allows us to store 2^7 times as many values.

Back

False

Answer explanation

Each additional bit doubles the amount of values we can store.

8 bits is 6 more than 2 bits. So that's doubling 6 times. 2x2x2x2x2x2 is 2 to the 6th power.

Front

You can represent the position of a light switch using a single binary digit.

Back

True

Answer explanation

A single binary digit allows us to store one of two values. A light switch can either be on or off, so this is true.

Front

What happens if I add two zeros to the end of a binary number? I.e. 110 -> 11000

Back

Its value is quadrupled (4x)

Answer explanation

110 in binary is 6 in decimal.

11000 in binary is 24 in decimal.

24 is 4 times as much as 6.

Also, remember that each additional binary digit doubles the amount of values/information. 2 more digits -> 2x2 -> 2 squared -> 4 times as much.

Front

What always happens when we sample analog information to represent it digitally?

Back

It is approximated at regular intervals and represented in bits

Front

You can represent the number of people in this class using only two binary digits

Back

False

Answer explanation

The maximum two digit binary number is 11, which is 3 in decimal/base 10/the normal numeric system.

Front

True or False: 8 bits makes 1 byte. The maximum decimal (base 10) value that can be represented by one byte is 256.

Back

False

Answer explanation

It's true that 8 bits = 1 byte. It is also true that you can represent 256 total values with 1 byte.

HOWEVER - the maximum 8 bit number is 255 (decimal/base 10) since you have to include zero (0) in the values you can represent.

256 (decimal/base 10) is the first 9 bit number.

Front

Which of these is the best definition of abstraction? Options: Abstraction allows us to represent complex information or perform complex tasks by showing underlying complexity., Abstraction allows us to represent complex information or perform complex tasks by hiding underlying complexity., Programming in machine language (binary) instead of a programming language like JavaScript., None of these are a good definition.

Back

Abstraction allows us to represent complex information or perform complex tasks by hiding underlying complexity.