Question

$\huge\underline{QUESTION}$
The alloy ' platinum-iridium cylinder' is used to define___
(a) The CGS unit of mass
(b) The SI unit of mass
(c) The CGS unit of length
(d) The SI unit of time​

Answer 1

in 1889 a platinum-iridium cylinder was used to define how much mass one kilogram represented.

so B is your answer

Answer 2

Answer:

In 1832 German mathematician Carl-Friedrich Gauss made the first absolute measurements of the Earth's magnetic field using a decimal system based on the use of the millimetre, milligram, and second as the base unit of time.

Explanation:

so The SI unit of mass is correct answer