What is meant by least count of a screw gauge?

What is meant by least count of a screw gauge?

Least count: The least count of the screw is defined as the distance moved by the tip of the screw when turned through one division of the head scale. Least count (LC) of the screw gauge = (pitch)/(total no.of divisions on the circular scale)

Is the screw gauge with smaller least count always better?

As less least count screw gauge measures very smaller length than that of more least count screw gauge. So first one whose pitch 0.5 mm is more accurate than second one.

What is the difference between least count and screw pitch of a screw gauge?

Least count of the screw gauge – The least count of the screw gauge can be calculated by the ratio of pitch and the total number of divisions. Least count of screw gauge = (Pitch)/(number of divisions) Least count of micrometer screw gauge = (1 mm)/(100) = 0.01 mm.

Why do we usually calculate the least count of an instrument?

The least count is related to the precision of an instrument; an instrument that can measure smaller changes in a value relative to another instrument, has a smaller “least count” value and so is more precise.

How can you control the least count of a screw gauge?

The least count of a screw gauge can be decreased by increasing the pitch and decreasing the total number of divisions on the circular scale .

What is the principle of a screw gauge?

The screw gauge works on the principle of movement. When the screw is rotated, there is a linear motion on the main scale of the screw gauge. This measurement is used to calculate small lengths. The distance moved by the spindle per rotation is known as pitch.

How to calculate the least count of the screw gauge?

As the he number of divisions on main scale are 10 to a centimeter, so the smallest division on main scale will be 1mm and it will be the pitch (p) of the screw gauge. The number of circular divisions is n= 100. The least count of a screw gauge is L.C = p/n = 1mm/100 = 0.01mm= (0.01/10)cm = 0.001cm = 10−3cm Answer verified by Toppr

What should the pitch of a screw gauge be?

For a screw gauge of 100 circular division, the pitch is 1 mm. A screw gauge of 100 divisions will move the cap scale along the main scale by 1/100 of mm-0.01 mm. This is the minimum value up to which a screw gauge can measure and is known as its least count.

When does a screw gauge have zero error?

Ans: If the zero of the head scale does not coincide with the zero of the pitch scale when the end of the movable screw is in contact with the stud, the screw gauge is said to have zero error. (v) If the zero of the head scale is 5 divisions above the line of graduation of the pitch scale when the gap is closed, what is the zero error?

How is the circular division of a screw gauge calculated?

The circular scale is designed in such a way that one complete rotation of the cap moves it horizontally by 1 mm on the main scale if circular scale cap moves it horizontally by 1 mm on the main scale if circular scale division is 100 and 0.5 mm in the main scale if the circular division is 50.