Given:
\[ F = ax^2 + bt^{1/2} \]
The dimensions of \( a \) are given by:
\[ [a] = \left[ \frac{F}{x^2} \right] = [MLT^{-2}][L]^{-2} = [ML^{-1}T^{-2}] \]
The dimensions of \( b \) are given by:
\[ [b] = \left[ \frac{F}{t^{1/2}} \right] = [MLT^{-2}][T^{-1/2}] = [MLT^{-5/2}] \]
Now, the dimensions of \( \frac{b^2}{a} \) are:
\[ \left[ \frac{b^2}{a} \right] = \frac{[M^2L^2T^{-5}]}{[ML^{-1}T^{-2}]} = [ML^3T^{-3}] \]
Figure 1 shows the configuration of main scale and Vernier scale before measurement. Fig. 2 shows the configuration corresponding to the measurement of diameter $ D $ of a tube. The measured value of $ D $ is:
Let $ P_n = \alpha^n + \beta^n $, $ n \in \mathbb{N} $. If $ P_{10} = 123,\ P_9 = 76,\ P_8 = 47 $ and $ P_1 = 1 $, then the quadratic equation having roots $ \alpha $ and $ \frac{1}{\beta} $ is: