TOPIC: UNITS OF MEASUREMENT AND DOSIMETRY 

🌟IMPORTANT POINTS TO REMEMBER

🔹Fundamental units: Fundamental units are units which are independent of each other and have their own standard (base).

🔹Derived units: Derived units are units which are not having their own standard (base) and are obtained from fundamental units.

🔹SI unit: In 1960, the new system of units – the SI units – was introduced.

🔹Units should be well-defined, reproducible, comparative, sensitive, objective, repeatable and linear.

🔹Air is used as the measurement material due to its availability, reproducibility, accuracy and sensitivity and its atomic number.

12. c