For a prism of refractive index 1.732, the angle of minimum deviation is equal to the angle of prism. Then the angle of the prism is

Options

A. `60^@`
B. `70^@`
C. `50^@`
D. none of these

Answer

A

Explanation

`n=(sin((A+delta_m)/(2)))/(sin""A/2)=(sin(2A)/(2))/(sin""A/2)=(sinA)/(sin""A/2)`
`therefore 1.732=(2sinA//2cosA//2)/(sinA//2)`
`therefore 0.866=cos""A/2`
`therefore 30^@=A/2`
`therefore A=60^@`