Why do JLPT N1 learners confuse 放射能 with 手数?

Both words occupy adjacent semantic territory, which is exactly why the JLPT uses them as distractors for each other on multiple-choice items. The fastest way to stop confusing them is to study them as a pair, write a one-sentence contrast in your own words, and drill the pair specifically rather than each word in isolation.

Is 放射能 or 手数 more common on JLPT N1?

Both appear in the JLPT N1 curriculum and either may show up on a given exam. Don't try to predict which one the test will choose — learn to distinguish them and you'll be safe regardless. Both belong to the General Nouns (6) theme of N1 vocabulary.

How do I practice this confusion pair?

Free option: visit /try and pick a confusion drill. Paid option: none — JLPT Mastery is free during launch. Whichever route you take, the engine specifically re-tests pairs you've gotten wrong rather than rotating through general vocabulary review.

JLPT N1 · Advanced · Meaning confusion

放射能 vs 手数

Q: What's the difference between 放射能 and 手数?

放射能 (ほうしゃのう) means "radioactivity" and 手数 (てすう) means "trouble, labor, handling". Managing 放射能 (radioactivity) involves significant 手数 (trouble/labor). A learner might confuse the 'nature' of the hazard with the 'effort' (手) required to manage its complex handling and safety protocols.

Why JLPT N1 learners mix up 放射能 (ほうしゃのう, “radioactivity”) and 手数 (てすう, “trouble, labor, handling”).

放射能

ほうしゃのう

radioactivity

noun

手数

てすう

trouble, labor, handling

noun

Theme: General Nouns (6)JLPT N1

Why these get confused

Managing 放射能 (radioactivity) involves significant 手数 (trouble/labor). A learner might confuse the 'nature' of the hazard with the 'effort' (手) required to manage its complex handling and safety protocols.

How to tell them apart

Anchor on the meaning, not the form. 放射能 (radioactivity) and 手数 (trouble, labor, handling) live in adjacent semantic territory. Memorize the boundary, not just each word.
Read the example sentences below. Seeing each word in its natural context builds a faster lookup than studying the dictionary form alone.

In a sentence

放射能 (radioactivity)

もう一つの面白いエネルギー源は、放射能の廃棄物質から取り出せる熱である。
もう一つの面白いエネルギー源は、放射能の廃棄物質から取り出せる熱である。

手数 (trouble, labor, handling)

手数料はかかりますか。
手数料はかかりますか。

How JLPT tests this pair

On JLPT N1, this pair shows up as a vocabulary meaning question. You see one word and pick its English equivalent from four options — one of which will be the other word in this pair, chosen as a distractor precisely because of the overlap.

Sample item

「放射能」の意味は？