Question 3 - Sample Paper 2 by Teachoo - Teachoo Sample Paper

Choose the correct option

"What is the main difference between UTF-8 and UTF-32 encoding schemes?"

A) UTF-8 uses 8 bits per character, while UTF-32 uses 32 bits per character

B) UTF-8 is a variable-width encoding scheme, while UTF-32 is a fixed-width encoding scheme

C) UTF-8 can encode all Unicode characters, while UTF-32 can encode only a subset of Unicode characters

D) All of the above are correct

Answer:

Answer by student

D) All of the above are correct

Detailed answer by teachoo

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• UTF-8 and UTF-32 are two encoding schemes that are based on Unicode, which is a standard for representing characters of different languages and scripts using a unique code point for each character.
• UTF-8 and UTF-32 differ in the way they encode the Unicode code points into binary sequences. Let’s look at each option and see why they are correct.

A) UTF-8 uses 8 bits per character, while UTF-32 uses 32 bits per character

• This option is correct because UTF-8 encodes each Unicode code point using one to four bytes (8 bits each), depending on the range of the code point. 
• On the other hand, UTF-32 encodes each Unicode code point using exactly four bytes (32 bits), regardless of the range of the code point. 

B) UTF-8 is a variable-width encoding scheme, while UTF-32 is a fixed-width encoding scheme

• This option is correct because UTF-8 uses different number of bytes to encode different Unicode code points, depending on their range. This means that the width of each character in UTF-8 can vary from one byte to four bytes. This makes UTF-8 more efficient and compact for encoding characters that have lower code points, such as ASCII characters.
• On the other hand, UTF-32 uses the same number of bytes to encode all Unicode code points, regardless of their range. This means that the width of each character in UTF-32 is fixed at four bytes. This makes UTF-32 more consistent and simple for encoding characters, but also more wasteful and bulky for encoding characters that have lower code points.

C) UTF-8 can encode all Unicode characters, while UTF-32 can encode only a subset of Unicode characters

• This option is correct because UTF-8 can encode all the Unicode code points that are defined in the standard, which currently range from U+0000 to U+10FFFF. This means that UTF-8 can represent any character of any language or script that is supported by Unicode.
• On the other hand, UTF-32 can encode only a subset of Unicode code points that are defined in the standard, which currently range from U+0000 to U+FFFF. This means that UTF-32 can represent only the characters that belong to the Basic Multilingual Plane (BMP) of Unicode, which covers most of the common languages and scripts, but not all of them.

D) All of the above are correct

• This option is correct because all the three options A, B and C are correct statements about the difference between UTF-8 and UTF-32 encoding schemes.

So, the correct answer is D) All of the above are correct.

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