Georgetown University researchers have discovered a new class of strong magnets that do not rely on rare-earth or precious ...
The BBC is not responsible for the content of external sites. Read about our approach to external linking.
Every now and again, I cook up 25 questions with a slightly higher difficulty tariff, and I think this week is such an occasion.
Some results have been hidden because they may be inaccessible to you
Show inaccessible results
Feedback