# The PDF quiz: ten questions for people who live in documents

> Points, paper sizes, standards and a bit of history. Ten questions, explanations after each answer, no sign-up, no email at the end.

Pick an answer to see whether you were right and why. Your score appears at the end.

Want the background behind the questions? Start with [a short history of the PDF](https://pdfjade.com/guides/history-of-the-pdf) or [A4 vs Letter](https://pdfjade.com/guides/a4-vs-letter-paper-sizes).

1. In what year did John Warnock write the memo that started the PDF project?
   - 1985
   - 1991
   - 1996
   - 2001
   Right.: 1991. The Camelot project memo dates from 1991. PDF 1.0 followed in 1993.

2. What does the "A" in PDF/A stand for?
   - Accessible
   - Archive
   - Adobe
   - Advanced
   Right.: Archive. PDF/A is the archiving standard, designed so files can still be displayed correctly decades later.

3. How many points are there in an inch?
   - 72
   - 96
   - 100
   - 300
   Right.: 72. PDF measures everything in points, 72 to the inch. A4 is 595 points wide.

4. Which is taller?
   - A4
   - US Letter
   - They're the same height
   - It depends on the printer
   Right.: A4. A4 is 297 mm tall, Letter is 279.4 mm. Letter is slightly wider, though.

5. Cut an A3 sheet in half across its long side. What do you get?
   - Two A2 sheets
   - Two A4 sheets
   - Two A5 sheets
   - Two Letter sheets
   Right.: Two A4 sheets. Each A size is half of the previous one, so A3 halves into two A4 sheets.

6. Which ISO standard number is PDF itself?
   - ISO 9001
   - ISO 216
   - ISO 32000
   - ISO 27001
   Right.: ISO 32000. PDF became ISO 32000-1 in 2008. PDF 2.0 is ISO 32000-2.

7. You can't select any text in a PDF. What's the most likely reason?
   - It's encrypted
   - It's a scan
   - It's PDF/A
   - It has too many pages
   Right.: It's a scan. A scanned page is an image of text. You need OCR to turn it into real characters.

8. What is Bates numbering mostly used for?
   - Numbering chapters in novels
   - Identifying every page in legal document productions
   - Counting PDF downloads
   - Marking photo copyright
   Right.: Identifying every page in legal document productions. Law firms and auditors stamp each page with a unique, continuous number such as ABC000123.

9. At 300 dpi, roughly how wide is an A4 page in pixels?
   - 595
   - 1240
   - 2480
   - 4960
   Right.: 2480. 8.27 inches × 300 = about 2480 pixels.

10. A drawn signature image on a PDF is…
   - A qualified digital signature
   - A simple electronic signature
   - Always invalid
   - The same as a certificate
   Right.: A simple electronic signature. It shows intent, which is enough for many documents, but it doesn't carry a certificate or protect the file from changes.

Source: https://pdfjade.com/guides/pdf-quiz