Question

which are used to measure time intervals​

Answer 1

The stopwatches and stop clocks are designed in such a way that they can accurately measure time intervals that are almost 1/10th or 1/100th of a second.

Answer 2

Answer:

Stopwatch.

Explanation:

A stopwatch is a small timepiece which can be held in one's hand. It is designed to measure the time that has been elapsed from a certain point of time when it has been activated to the time at which the piece has been deactivated.