Why it is necessary to close the shutters of glass case for an accurate measurement in the experiment of a beam balance
Answers
Explanation:
1. A Vernier Calliper has two scales–one main scale and a Vernier
scale, which slides along the main scale. The main scale and Vernier
scale are divided into small divisions though of different
magnitudes.
The main scale is graduated in cm and mm. It has two fixed jaws, A
and C, projected at right angles to the scale. The sliding Vernier scale
has jaws (B, D) projecting at right angles to it and also the main scale
and a metallic strip (N). The zero of
main scale and Vernier scale coincide
when the jaws are made to touch each
other. The jaws and metallic strip are
designed to measure the distance/
diameter of objects. Knob P is used to
slide the vernier scale on the main
scale. Screw S is used to fix the vernier
scale at a desired position.
2. The least count of a common scale
is 1mm. It is difficult to further
subdivide it to improve the least
count of the scale. A vernier scale
enables this to be achieved.