File Extensions and File Formats Notes for SSC Exams

File extensions are a high-search and scoring topic of SSC Computer Knowledge, because the questions are direct: which extension belongs to which type of file. These file extensions and formats notes for SSC give you the full list in tables with the full forms and practice questions. Read it with the MS Office Notes and MS Windows Notes notes.

What Is a File Extension?

A file extension is the short code after the dot in a file name that tells the type of the file and the program that can open it. For example, in notes.docx, docx is the extension.

Document, Spreadsheet and Presentation Files

Image Files

Audio and Video Files

Compressed, Web and Executable Files

Lossy compression removes some data to reduce the size (JPEG, MP3). Lossless compression keeps all the data (PNG, ZIP, FLAC).

How File Names and Extensions Work

• A file name has two parts: the name and the extension, separated by a dot, such as report.docx.
• Windows file names can have up to 255 characters and cannot contain the characters \ / : * ? " < > |.
• The operating system uses the extension to choose the program that will open the file.
• Changing the extension does not convert the file; it may make the file unreadable.
• Windows may hide the extension of known file types. It can be shown from the View settings of the File Explorer.
• The extension of a file is generally 2 to 4 characters.

More Document and Data Formats

More Image, Audio and Video Formats

Raster (bitmap) images are made of pixels and lose quality when enlarged (JPG, PNG, GIF, BMP). Vector images are made of mathematical shapes and do not lose quality (SVG, AI, EPS, CDR).

System, Programming and Web Files

Compression and Formats in Short

• Lossy compression permanently removes some data to make the file smaller (JPEG, MP3, MP4).
• Lossless compression keeps all the original data (PNG, FLAC, ZIP).
• Archive formats (zip, rar) put many files in one package.
• A codec is a program that compresses and decompresses audio or video.
• Streaming plays audio or video while it is being downloaded.
• Encryption protects a file with a password so that others cannot read it.

Important Questions Explained

Question 1: What is the extension of an MS Excel 2016 file?
Answer: .xlsx

Question 2: Which image format supports animation?
Answer: GIF.

Question 3: Which format supports a transparent background and lossless compression?
Answer: PNG.

Question 4: What is the full form of PDF?
Answer: Portable Document Format.

Question 5: What is the extension of an executable file?
Answer: .exe

Question 6: Which extension is used for a compressed file?
Answer: .zip (also .rar and .7z).

Quick Tips to Remember

• Learn the three Office extensions: .docx, .xlsx and .pptx.
• Link GIF with animation, PNG with transparency and JPEG with photos.
• Remember .exe as the program and .zip as the compressed file.
• Remember that .mp3 is audio and .mp4 is video.
• Learn that .html is for web pages and .apk is for Android apps.

Common Mistakes to Avoid

• Mixing .mp3 (audio) and .mp4 (video).
• Writing .xls as the latest Excel extension.
• Confusing GIF and PNG.
• Writing .txt for a Word file.
• Mixing the full forms of JPEG and PNG.

Quick Revision Points

• Word .docx; Excel .xlsx; PowerPoint .pptx.
• PDF = Portable Document Format (Adobe).
• JPEG = photos, lossy; PNG = lossless with transparency; GIF = animation.
• MP3 = audio; MP4 = video; EXE = program; ZIP = compressed.
• HTML = web page.

Practice Questions With Answers

1. The extension .docx belongs to?
   Answer: MS Word (Document).
2. The full form of PDF is?
   Answer: Portable Document Format (Adobe).
3. Which image format supports animation?
   Answer: GIF (256 colours).
4. Which extension is for a program file?
   Answer: .exe (Executable).
5. Which extension is for an audio file?
   Answer: .mp3 (Compressed audio).
6. What is the extension of a PowerPoint file?
   Answer: .pptx (Presentation).
7. Which file format is lossless and supports transparency?
   Answer: PNG (Portable Network Graphics).
8. What is a .zip file?
   Answer: Compressed file (Archive).
9. Which extension is used for a web page?
   Answer: .html (HyperText Markup Language).
10. Which extension is for an Android app?
    Answer: .apk (Android package).

More Practice Questions With Answers

1. Which format is best for photographs?
   Answer: JPEG (Lossy).
2. Which extension is a vector image?
   Answer: .svg (Scalable).
3. Which extension stores an Android app?
   Answer: .apk (Android).
4. Which extension is a disc image?
   Answer: .iso (Image of a disc).
5. Which image format has no compression?
   Answer: BMP (Large size).
6. Which audio format is lossless?
   Answer: FLAC (Compressed).
7. Which extension is Java compiled code?
   Answer: .class (Bytecode).
8. Which extension is a backup file?
   Answer: .bak (Backup).
9. Which characters cannot be used in a file name?
   Answer: \ / : * ? " < > | (Windows rule).
10. Which extension is an Excel file with macros?
    Answer: .xlsm (Macro enabled).
11. Which extension is a data format using tags?
    Answer: .xml (Markup).
12. In which year did Adobe create PDF?
    Answer: 1993 (Portable Document Format).

How to Practise This Chapter

1. Read the tables once and learn the key facts by heart.
2. Revise the quick revision points the next day.
3. Attempt the practice questions above without looking at the answers.
4. Solve a full SSC CGL Tier 1 mini mock to test your general awareness.
5. Check the previous year papers to see how SSC asks computer questions.

Related Notes and Practice Papers

• MS Office Notes
• MS Windows Notes
• Computer Software Notes
• Computer Knowledge Notes for SSC
• SSC CGL Tier 1 Mini Mock

Explore More SSC Subjects

SSC exams test many subjects, so connect this topic with the related subjects below:

• General Science Notes
• General Awareness Notes
• Quantitative Aptitude Notes
• Reasoning Notes
• Electrical Engineering (SSC JE) Notes
• All SSC subjects and notes

Frequently Asked Questions

What is a file extension?

A file extension is the code after the dot in a file name that shows the type of the file.

What is the extension of an MS Word file?

It is .docx for newer versions and .doc for older versions.

What is the extension of an Excel file?

It is .xlsx for newer versions and .xls for older versions.

What is the extension of a PowerPoint file?

It is .pptx for newer versions and .ppt for older versions.

What is the full form of PDF?

PDF stands for Portable Document Format.

Which image format supports animation?

GIF supports simple animation.

What is the difference between lossy and lossless compression?

Lossy compression removes some data to reduce the size, while lossless compression keeps all the data.

What is the extension of a compressed file?

Common compressed file extensions are .zip, .rar and .7z.

How many questions come from file extensions in SSC exams?

One question usually comes from file extensions or formats.

What is the difference between raster and vector images?

Raster images are made of pixels and lose quality when enlarged, while vector images are made of mathematical shapes and keep their quality at any size.

Which characters are not allowed in a Windows file name?

The characters \ / : * ? " < > | are not allowed in a Windows file name.

What is the difference between JPEG and PNG?

JPEG uses lossy compression and is best for photos, while PNG uses lossless compression and supports a transparent background.