<P> Negative zero error refers to the case when the jaws of the vernier caliper are just closed and the reading is a negative reading away from the actual reading of 0.00 mm . If the reading is 0.08 mm, the zero error is referred to as + 0.08 mm . If positive, the error is subtracted from the mean reading the instrument reads . Thus if the instrument reads 4.39 cm and the error is + 0.05, the actual length will be 4.39 - 0.05 = 4.34 cm . If negative, the error is added to the mean reading the instrument reads . Thus if the instrument reads 4.39 cm and as above the error is - 0.05 cm, the actual length will be 4.39 + 0.05 = 4.44 cm . (Considering that, the quantity is called zero correction which should always be added algebraically to the observed reading to the correct value .) </P> <P> Zero Error (Z.E) = + or - n * Least Count (L.C). </P>

What is meant by zero error of vernier calipers