Question

"what do we call the principal si units that are used to derive all other si units?"

Answer 1

HEY MATE

UR ANSWER IS

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the base unit  bcoz they are also called the fundamental unit .they are standard units agreed from the internationally for mesurment . they are used to derive the other unit . they are seven type =

1. The metre (m)

2.The kilogram (kg)

3. The second (s)

4. The ampere (A)

5. The kelvin (K)

6. The candela (cd)

7. The mole (mol)

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THANKS

Answer 2

Combination of derived and base units is accessed to show other derived units.

We call the principal of Si units as fundamental units.

Others are known as derived units.  

Units which are measured some physical quantities (length, mass, electric current, and time) called fundamental units.  

The unit that divided by time called derived units.