平成28年度秋期 ITパスポート試験問90

This question's explanation and your answers so far.

問90

頻出度★☆☆

次のうち, 通信可能な最大距離が最も短いものはどれか。

出典　平成28年度秋期 ITパスポート試験問90

解説

問 90

Incorrectア
Bluetooth is a standard for wirelessly connecting digital devices, and the common Class 2 has a communication range of about 10 m. This is far longer than NFC's roughly 10 cm, so it is not the shortest.
Incorrectイ
IrDA is short-range data communication using infrared light, with a communication range of about 1 m. This is longer than NFC's roughly 10 cm, so it is not the shortest.
ウ
正解 The correct answer is choice ウ, NFC. The communication range of NFC (Near Field Communication) is only about 10 cm, extremely short and the shortest among the choices. It uses the feature of communicating simply by holding a device close, and is used for things like transit IC cards and smartphone tap-to-pay. Comparing the typical maximum range of each method gives NFC (about 10 cm) < IrDA (about 1 m) < Bluetooth (about 10 m) < Wi-Fi (about several tens of meters), so NFC can be judged to be the shortest.
Incorrectエ
Wi-Fi is a wireless LAN standard, and even indoors its communication range is about several tens of meters, placing it among the longest of the choices — the exact opposite of the shortest.

ここがポイント

Remember the relative communication ranges of the main short-range wireless methods: NFC (a few cm) < IrDA (about 1 m) < Bluetooth (about 10 m) < Wi-Fi (tens of meters or more).
A key feature of NFC is that it is very-short-range communication of about 10 cm that works simply by holding a device close, and it is used for IC cards and smartphone payments.

用語

解答問90ウ