MCQ
In an experiment the angles are required to be measured using an instrument, $29$ divisions of the main scale exactly coincide with the $30$ divisions of the vernier scale. If the smallest division of the main scale is half- a degree $(= 0.5^o )$, then the least count of the instrument is
- A$1^o$
- B$\frac{1}{2}^o$
- ✓$1'$
- D$( \frac{1}{2})'$