The angle of minimum deviation produced by a thin prism in air is $\delta_1$. If it is immersed in water the angle of minimum deviation is

$$\left[\mathrm{a}_{\mathrm{g}}=\frac{3}{2}, \mathrm{a}_{\mathrm{w}}=\frac{4}{3}\right]$$

For a symmetric (equilateral) prism, the prism formula can be written as

For a ray of light, the critical angle is minimum, when it travels from

Critical angle of light passing from glass to air is minimum for wavelength of