State the most appropriate instrument, or instruments, for the measurement of the following.
the diameter of a wire of diameter about 
the resistance of a filament lamp
the peak value of an alternating voltage
The mass of a cube of aluminium is found to be 
with an uncertainty in the measurement of 
. Each side of the cube has a length of 
. Calculate the density of aluminium with its uncertainty. Express your answer to an appropriate number of significant figures.
.
