A $u-v$ graph is plotted for a convex lens of focal length $10 \mathrm{cm}$. What will be the values of $u$ and $v$ corresponding to the point of intersection of the hyperbola with the bisector of the angle between the X-axis and the Y-axis?

A student has taken the readings for index correction in the beginning for calculation of $u$ and $v$. The reading for index correction is to be taken again in which of the following conditions?

Three observations were taken to find the refractive index of the material of glass slab. The reading for the mark on the paper $\left(R_1\right)$, The reading on the mark of the paper with slab $\left(R_2\right)$ , and the reading for lycopodium powder $\left(R_3\right)$. Which of the following will be the correct formula for finding the refractive index?