The seven SI base units are the second, metre, kilogram, ampere, kelvin, mole and one more. Which is the seventh?
The hertz, for frequency
The newton, for force
The litre, for volume
The candela, for luminous intensity✓الإجابة الصحيحة
الشرح
The candela measures how much visible light a source sends out in a given direction, weighted for the response of the human eye. The newton and the hertz are SI units, but derived ones, and the litre is not an SI unit at all.