1 picometre = how many centimetres?

Correct answer: d 10⁻¹⁰

1 pm = 10⁻¹² m and 1 m = 10² cm, so 1 pm = 10⁻¹⁰ cm.

Why the other options are wrong

• a 10⁻¹⁸: 10⁻¹⁸ is the multiplier of atto (a); 1 pm = 10⁻¹² m = 10⁻¹² × 10² cm = 10⁻¹⁰ cm.
• b 10⁻¹⁶: Not 10⁻¹⁶; 1 m = 10² cm, so the exponent rises by 2, it does not fall further.
• c 10⁻¹²: 10⁻¹² is the value in metres; to get centimetres multiply by 10².