Questions

Because of high stability, large Q (Quality Factor) & the frequency that doesn't drift with aging. Crystal is used as a clock source most of the times.

A hard real-time system guarantees that critical tasks complete on time. This goal requires that all delays in the system be bounded from the retrieval of the stored data to the time that it takes the operating system to finish any request made of it. A soft real time system where a critical real-time task gets priority over other tasks and retains that priority until it completes. As in hard real time systems kernel delays need to be bounded

In the given puzzle, the logic is the product of the number and its preceeding number gives the result.

9 = 9 x 8 = 72

8 = 8 x 7 = 56

7 = 7 x 6 = 42

6 = 6 x 5 = 30

5 = 5 x 4 = 20

Similarly,

3 = 3 x 2 = 6.

Udaipur, a city in the state of Rajasthan which was named after the Maharana Udai Singh - II, is known for its beautiful artificial lakes around the city and lavish royal residences.

Thus, Udaipur nickname is City of Lakes in India.