Solve the following exercise questions: A. Darken the circle for the correct option. B. Fill in the blanks.

Here are the solutions to the exercise questions:

A. Darken the circle for correct option in OMR Sheet:

1. a) second
   • Explanation: The International System of Units (S.I.) unit for time is the second.
2. c) Both Delhi and Jaipur
   • Explanation: There are Jantar Mantar observatories located in both Delhi and Jaipur.
3. a) $\text{m/s}$
   • Explanation: The S.I. unit of speed is meters per second, derived from the S.I. units of distance (meter) and time (second).
4. c) Quartz watches
   • Explanation: Quartz watches use a vibrating crystal to measure time with high accuracy compared to the other options.
5. c) Odometer
   • Explanation: An odometer is an instrument used in vehicles to measure the total distance traveled.

B. Fill in the blanks:

1. A digital watch has no dial or moving hands.
2. Kilogram is the S.I. unit of mass.