Physics · JEE | Ray Optics and Optical Instruments

For a thin prism of small refracting angle \( A \) and refractive index \( n_{21} \), the angle of minimum deviation \( D_m \) is expressed as:

1. A
   \( D_m = \frac{n_{21} - 1}{A} \)
2. B
   \( D_m = (n_{21} + 1)A \)
3. C
   \( D_m = (n_{21} - 1)A \)
4. D
   \( D_m = (1 - n_{21})A \)