I would measure its length in inches, its weight in ounces, and its screen brightness in lumens.
a ruler, tape measure, etc.
any instrument that can measure length.
Whatβs the best unit of measurement for a phone?
a postage scale or nutrition scale
mm
Probably inches or centimeters.
None of them. An ounce (not once) will measure its mass. To get weight you need ounce-weight.
The best unit is a litre.
It probably depends on what cell phone you have.
The best unit for measuring the length of a pencil is inches.
Gram
pounds
Feet
A millimetre.
meters