The angle between the minute hand and the hour hand of a clock when the time is

The angle between the minute hand and the hour hand of a clock when the time is 8:30, is:

How many times in a day, are the hands of a clock in straight line but opposite

How many times in a day, are the hands of a clock in straight line but opposite in direction?

At what time between 4 and 5 o’clock will the hands of a watch point in opposite

At what time between 4 and 5 o’clock will the hands of a watch point in opposite directions?

At what time between 9 and 10 o’clock will the hands of a watch be together?

At what time between 9 and 10 o’clock will the hands of a watch be together?