Question

If the smallest division of a vernier is longer than the smallest division of its primary scale, the Vernier is known as ____

• A. Simple Vernier
• B. Retrograde Vernier
• C. Double Vernier
• D. Direct Vernier

Answer 1

The correct option is B Retrograde Vernier

The direct vernier has divisions which are slightly shorter than those of the main scale	Retrograde vernier has divisions which are slightly longer than those of the main scale.
Reading increases in a direction to that of the main scale.	Reading increases in a direction opposite to that of the main scale.

• For both the vernier, least count = S/n

Where S = Value of smallest division on main scale
n = No. of divisions on vernier.

• The least count of the vernier is equal to the difference in length of one division of the main scale and one divisions of the vernier scale.

Note: In direct vernier, graduation increase in the same direction in which graduations of the main scale increases.