If the smallest division of a Vernier is longer than the smallest division of its primary scale, then the Vernier is called
- ADirect vernier
- BDouble vernier
- CSimple vernier
- DRetrograde vernierCorrect
Solution
Concept
Direct and retrograde verniers
Step-by-step solution
1. Direct vernier: smallest division of the vernier is shorter than the smallest division of the main scale. 2. Retrograde vernier: smallest division of the vernier is longer than that of the main scale and the vernier numbering runs opposite to the main scale.
Explanation
The smallest division of a direct vernier is shorter than that of the main scale, while in a retrograde vernier it is longer. A retrograde vernier is read in the direction opposite to the main scale.
Shortcut
Retrograde = Reverse = longer vernier division.
Common mistake
Mixing up direct and retrograde.
Correct answer: D) Retrograde vernier