Multiple choice

Which of the following is a physical change?

  1. Radioactive decay

  2. Photosynthesis

  3. Magnetising a needle

  4. Rusting of iron

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A physical change doesn't produce new substances and is often reversible. Magnetizing a needle only aligns magnetic domains - the material remains the same and can be demagnetized. Radioactive decay (A) changes elements, photosynthesis (B) produces glucose from CO₂ and water, and rusting (D) creates iron oxide - all are chemical changes.