They are both as accurate as you measure them to be. However an objects mass is an intrinsic property of the the object, while an objects weight will vary depending on the gravity field in which it is placed.
A mass may be accurately measured using a beam balance, against known reference standards.
For small masses, such as mg, one would probably use an electronic balance, whose performance was known over the range being tested.
To gain knowledge of this performance, you would weigh a series of small calibration masses, and compare the results with those indicated on the electronic scale.
The most known is a balance and a scale balance.
Comparator Balances
The triple beam balance
yes
A triple-beam balance scale
No matter what one is measuring, there must be a standard against which to measure it, and a means of comparing it to the standard. In the case of measuring charge, the object being measured must be compared to a standard charge by some means such as measuring their mutual attraction or repulsion, moving it at a known velocity while the resulting magnetic field is compared to a standard, or some other means. Measuring the brightness of a light, a time interval, or anything else requires some such operation. For mass, there is a particularly easy way to make measurements because the Earth's gravity provides a very accessible and consistent reference. All that is needed is a standard mass and a balance. So measuring an object's mass is usually easier than most of its properties. Lengths can also be rather easy.
Triple beam balances usually read in .1 gram increments. That's equivalent to 100 milligrams. That doesn't mean that the instrument is actually ACCURATE or CALIBRATED to within .1 grams-- only that the instrument's readability is .1 grams. A poor quality or poorly maintained instrument might not read accurately to the true value of the weighed object's mass. It's possible to buy more precise triple beam balances capable of reading in milligrams (.001g) but they are expensive and more difficult to properly maintain. For this reason, most modern high precision balances are digital.
an exposure rate survey instrument
Earth.
sonar.
It is not; there are more precise measurements.
measuring tape
What is the most suitable instrument for measuring the weight of a cup
Its 12.000
There are many. Though the ones most commonly used are the ruler and the measuring stick.
There are a few instruments that can theoretically be used to measure flour. The most common measuring tool is a measuring cup.
the mass measuring tools are: standard balance senstive balance and there are lot more types
Strictly, it's measuring weight, but most are calibrated to give mass.
An EDM or electronic distance measure. These are used by engineers in the construction industry for measuring distances. Hope this helps.
This instrument is an electronic micropipette.
This instrument is an electronic micropipette.