The Vernier scale on a universal bevel protractor has how many divisions on each side of zero?

The Vernier scale on a universal bevel protractor has how many divisions on each side of zero?

• A. 8
• B. 10
• C. 12
• D. 24

Answer: (C)

The Vernier scale on a universal bevel protractor provides finer angular readings by using a sliding scale whose divisions align with a different count of main-scale divisions. On this instrument, there are twelve divisions on each side of zero, so twelve Vernier divisions span the same length as eleven main-scale divisions. This makes each Vernier division equal to 11/12 of a main-scale division, and the difference between one main-scale division and one Vernier division is 1/12 of a main-scale division. Therefore the least count is 1/12 of a degree (if the main scale is in degrees), which is 5 minutes of arc. The two sides of zero simply extend this fine reading ability in either direction around zero.

The Vernier scale on a universal bevel protractor provides finer angular readings by using a sliding scale whose divisions align with a different count of main-scale divisions. On this instrument, there are twelve divisions on each side of zero, so twelve Vernier divisions span the same length as eleven main-scale divisions. This makes each Vernier division equal to 11/12 of a main-scale division, and the difference between one main-scale division and one Vernier division is 1/12 of a main-scale division. Therefore the least count is 1/12 of a degree (if the main scale is in degrees), which is 5 minutes of arc. The two sides of zero simply extend this fine reading ability in either direction around zero.