IPA IP 2021 Question 89

Topic: Basic Theory

A question IPA Japan published in 令和3年度 ITパスポート試験 公開問題 問89, translated into English. ITPEC is based on the same exams.

Same question on ITPEC: Oct 2024 Q1 +1 more

Which of the following is the combination of terms or phrases to be inserted into blanks A through C in the description below concerning a method for representing information?

Data that represents information by using a continuous, variable physical volume (length, angle, voltage, etc.) is called A data, and data that represents information by using discrete numerical values is called B data. A CD that is used for the distribution of music and songs is an optical disc medium that stores information as C data.

OptionABC

Explanation

A: analog, B: digital, C: digital — the question tests the two ways of representing information and which one a music CD uses.

Data that represents information with a continuously varying physical quantity such as length, angle or voltage is analog data (blank A). Data that represents information with discrete numerical values is digital data (blank B).

A music CD samples the sound wave at fixed intervals and stores each sample as a binary number, read optically from the disc. It therefore stores digital data (blank C); the player converts the numbers back into an analog signal for the speakers.

Answer (b)

Why not others:

  • •(a) — defines A and B correctly but calls the CD analog, confusing the analog sound it reproduces with the discrete samples it stores
  • •(c) and (d) — swap the two definitions: a continuous quantity is analog, and discrete numerical values are digital

Key rule: Continuous physical quantity = analog; discrete numerical values = digital. CDs, DVDs, USB memory and other computer media store digital data even when the content began as analog sound or images.

Basic Theory · AI-written, may contain errors

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This question comes from the past questions IPA Japan publishes, translated into English by ITPEC Practice. ITPEC Practice is an independent study tool and is not affiliated with IPA or ITPEC. See the original paper (PDF) or Report an issue.