80. AQA GCSE (8525) SLR13 – 3.3 Characters

What is the minimum number of bits needed to represent the 26 letters of the alphabet?

• 5 bits

• 7 bits

• 4 bits

• 6 bits

Answer explanation

To represent 26 letters, we need at least 5 bits (2^5 = 32, which is the smallest power of 2 greater than 26). Therefore, the minimum number of bits needed is 5 bits.

How many unique characters can be represented by 7 bits?

• 32 characters

• 256 characters

• 128 characters

• 64 characters

Answer explanation

7 bits can represent 2^7 unique combinations, which equals 128. Therefore, 128 unique characters can be represented by 7 bits.

What does ASCII stand for?

• American Standard Code for Information Interchange

• American Symbol Code for International Interchange

• Automated Standard Code for Information Interchange

• American Standard Code for Interconnected Information

Answer explanation

ASCII stands for American Standard Code for Information Interchange, making it the correct choice.

How many characters does the extended ASCII character set identify?

• 128 characters

• 256 characters

• 1024 characters

• 512 characters

Answer explanation

The extended ASCII character set identifies 256 characters, which is the correct choice among the options provided.

What is the purpose of Unicode?

• To replace ASCII with a simpler system

• To represent numbers only

• To provide a fully international and multilingual character set

• To encode symbols for mainframe computers

Answer explanation

The purpose of Unicode is to provide a fully international and multilingual character set, allowing for the representation of various languages and symbols.

What is the original bit count of Unicode?

• 32-bit

• 24-bit

• 16-bit

• 8-bit

Answer explanation

The original bit count of Unicode is 16-bit, allowing for a range of 65,536 unique characters to be represented.

How many characters can be represented by 8 bits?

• 1024 characters

• 512 characters

• 256 characters

• 128 characters

Answer explanation

8 bits can represent 256 different characters because each bit has 2 possible values (0 or 1), and 2^8 = 256.

What does each character in a computer system have?

• A unique texture

• A unique sound

• A unique binary code

• A unique color

Answer explanation

Each character in a computer system has a unique binary code, which is used to represent it in the system. This binary code allows the computer to process and manipulate the characters effectively.

What is the significance of the number 32 in ASCII?

• It is the total number of control characters

• It represents a space

• It is the binary code for 'A'

• It represents the number '2'

Answer explanation

The significance of the number 32 in ASCII is that it represents a space, not the total number of control characters, binary code for 'A', or the number '2'.

What does UTF-8 stand for?

• Universal Transformation Format - 8 bit

• Universal Text Format - 8 bit

• Unicode Transformation Format - 8 bit

• Unicode Text File - 8 bit

Answer explanation

UTF-8 stands for Unicode Transformation Format - 8 bit, making it the correct choice among the options provided.