Question

what is the difference between (a) derived and fundamental quantities and (b) dimensions and units?

Explanation:

(a) Fundamental quantities are basic and independent, like mass, length, time. Derived quantities are combinations of fundamental ones, e.g., speed (length/time). (b) Dimensions represent the nature of a physical quantity in terms of fundamental quantities (e.g., [L] for length). Units are standards for measuring quantities, like meter for length.

Answer:

(a) Fundamental quantities are basic and independent; derived are combinations of fundamentals. (b) Dimensions show the nature of a quantity in terms of fundamentals; units are standards for measurement.