Physics - Error Question with Solution | TestHub

A vernier's main and vernier scales have expansion coefficients ${\alpha }_1$ and ${\alpha }_2$. A rod's front edge crosses main division $N$; main division $(N+2)$ coincides with the second vernier division. Initially $10$ vernier divisions equal $9$ main divisions. On a small temperature rise the instrument's reading remains unchanged. Neglect rod expansion. For this numerical version set $N=7$. Find $\frac{{\alpha }_1}{{\alpha }_2}$.