IPA IP 2025 Question 71
A question IPA Japan published in 令和7年度 ITパスポート試験 公開問題 問71, translated into English. ITPEC is based on the same exams.
Which of the following is the appropriate combination of words to be inserted into blanks A and B in the description below concerning radio waves used for mobile phones?
Radio waves have the property that the A the frequency, the more easily they go around obstacles and the more easily they reach even behind obstacles. Among the frequencies used for mobile phones in Japan, the frequency band from the 700 B band to the 900 B band is called the platinum band because, among other reasons, it has this property and connects easily.
Explanation
A: lower, B: MHz — lower-frequency radio waves bend around obstacles more easily, and Japan’s platinum band runs from about 700 MHz to 900 MHz.
The longer its wavelength, the more a radio wave diffracts: it bends around buildings and reaches into their shadows and indoors. The wavelength is the speed of light divided by the frequency, so a lower frequency means a longer wavelength. So A is “lower”.
“Platinum band” is the name used in Japan for the mobile phone bands of about 700 MHz to 900 MHz. A signal there reaches behind obstacles and into buildings and travels far, so phones connect easily and fewer base stations cover an area. Bands in GHz, such as 3.7 GHz or the 28 GHz band of 5G, carry more data but travel in straighter lines and are blocked more easily. So B is “MHz”: 700 to 900 GHz is far above any band used for mobile phones.
Answer (d)
Why not others:
- •(a) — both wrong: a higher frequency travels straighter, and 700 to 900 GHz is not a mobile phone band
- •(b) — MHz is right, but a higher frequency bends around obstacles less, not more
- •(c) — lower is right, but the platinum band is measured in MHz, not GHz
Key rule: The lower the frequency, the longer the wavelength and the better a radio wave reaches around obstacles; the higher the frequency, the more data it carries but the straighter it travels.
Networks · AI-written, may contain errors
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.