Match the pair:
Group 'A' \(\hspace{3cm}\) Group 'B'
Substance \(\hspace{3cm}\) Refractive index
\(\hspace{1cm}\) Air \(\hspace{3cm}\) (a) \( 1.33 \)
\(\hspace{1cm}\) Water \(\hspace{3cm}\) (b) \( 1.46 \)
\(\hspace{1cm}\) Glass \(\hspace{3cm}\) (c) \( 1.0003 \)
Two light beams fall on a transparent material block at point 1 and 2 with angle \( \theta_1 \) and \( \theta_2 \), respectively, as shown in the figure. After refraction, the beams intersect at point 3 which is exactly on the interface at the other end of the block. Given: the distance between 1 and 2, \( d = 4/3 \) cm and \( \theta_1 = \theta_2 = \cos^{-1} \frac{n_2}{2n_1} \), where \( n_2 \) is the refractive index of the block and \( n_1 \) is the refractive index of the outside medium, then the thickness of the block is cm. 