концентрация

концентрация

Concentration; the action or power of focusing attention or the amount of a substance in a mixture.

Here, 'концентрация' is used to denote mental focus or attention.

Я достигаю оптимальной концентрации, когда работаю в тишине.

I achieve optimal concentration when working in silence.

In this sentence, 'концентрация' is used to refer to the proportion of a substance within a mixture.

Концентрация соли в этом растворе слишком высока.

The concentration of salt in this solution is too high.

This usage of 'концентрация' refers to the grouping or density of people in a given area.

При концентрации многих человек в небольшой комнате воздух становится душным.

When many people are concentrated in a small room, the air becomes stuffy.