Yes, in most instances, answering short calls, texts, and emails would meet the definition of hours worked found in the Industrial Welfare Commission Orders, Section 2:
“Hours worked” means the time during which an employee is subject to the control of an employer, and includes all the time the employee is suffered or permitted to work, whether or not required to do so.”
These small increments of time are difficult to track and frequently are disregarded as “de minimis” time that is insignificant. In fact, the federal Fair Labor Standards Act allows employers to disregard small amounts of time as de minimis time. Disregarding these small increments is no longer advisable in California.
In 2018 the California Supreme Court held that the de minimis rule has not been adopted by California laws. According to the court, don’t allow employees to routinely work for minutes off the clock without being paid—because California labor laws require pay for “all hours worked.”