Advertisements
Advertisements
Question
What do you mean by zero error of a screw gauge? How is it accounted for?
Advertisements
Solution 1
Due to mechanical errors, sometimes when the anvil and spindle end are brought in contact, the zero mark of the circular scale does not coincide with the base line of main scale. It is either above or below the base line of the main scale, in which case the screw gauge is said to have a zero error. It can be both positive and negative.
It is accounted by subtracting the zero error (with sign) from the observed reading in order to get the correct reading.
Correct reading = Observed reading - zero error (with sign)
Solution 2
If the zero of the circular scale does not coincide with the zero of the main scale (pitch scale), this is known as zero error. There are two types of zero error -
(a). If the zero of the circular scale remains below the line of graduation then it is called positive zero error
(b). If the zero of the circular scale lies above the line of graduation then it is called negative zero error
For positive zero error correction, the zero error should always be subtracted from the observed reading
For negative zero error correction, the zero error must be added to the observed reading.
APPEARS IN
RELATED QUESTIONS
The wavelength of light of a particular colour is 5800 Å.
Express it in nanometre.
State three uses of the vernier callipers.
The pitch of a screw gauge is 1 mm and the circular scale has 100 divisions. In measurement of the diameter of a wire, the main scale reads 2 mm and 45th mark on the circular scale coincides with the base line. Find
(i) The least count and
(ii) The diameter of the wire.
(a) A vernier scale has 20 divisions. It slides over the main scale, whose pitch is 0.5 mm. If the number of divisions on the left hand of the zero of vernier on the main scale is 38 and the 18th vernier scale division coincides with the main scale, calculate the diameter of the sphere, held in the jaws of vernier callipers.
(b) If the vernier has a negative error of 0.04 cm, calculate the corrected radius of the sphere.
What do you understand by the following term as applied to micrometre screw gauge?
Sleeve cylinder
Name the measuring employed to measure the thickness of a paper.
Consider the following case where the zero of vernier scale and the zero of the main scale are clearly seen. If L.C. of the vernier calipers is 0.01 cm, write the zero error and zero correction of the following.
In a vernier calliper, (N + 1) divisions of the vernier scale coincide with N divisions of the main scale. If 1 MSD represents 0.1 mm, the vernier constant (in cm) is ______.
