Question

How time is measured when pendulum clocks were not available?On what principle are modern electronic watches work

Answer 1

Time was measured by Sundials when pendulum clocks were not available.

CERTIFIED ANSWER. the principle on which the modern electronic watches are based on is quartz. quartz is a vibrating electronically driven crystal. the watches are operated on the vibrations of the crystals.

Answer 2

the answer is sundials