Avernier caliper consists of two scales: a main scale and a vernier scale. the vernier scale is made by dividing 19 main scale divisions into 20 parts. the least count of the main scale is 1mm. a) what is the least count of this vernier caliper.
b) what is the uncertainty of this instrument.
c) describe zero errors associated with vernier calipers and reasons to occur zero errors.

Explanation:

a ) one vernier scale division = 19/20 mm.

Least count of vernier scale

= one main scale division - one vernier scale division

= ( 1 - 19 / 20) mm

= .05 mm

b ) uncertainty in the instrument = .05 mm / 1 mm

= 5 %

c ) When the zero mark of the vernier scale does not correspond to the zero  

mark of the main scale then there is likelihood of error creeping in the reading by the scale. It is called zero error.  

an ion is a charged atom or molecule. it is charged because the number of electrons do not equal the number of protons in the atom or molecule. an atom can acquire a positive charge or a negative charge depending on whether the number of electrons in an atom is greater or less then the number of protons in the atom.

the current is 0.6

voltage ÷ resistance = current

so 12 ÷ 20 = 0.6