When two prisms composed of different materials are properly combined, it is possible to

Step-by-step solution

When two prisms of different materials are combined, the net deviation is given by = ₁ + ₂ = A₁( ₁ - 1) + A₂( ₂ - 1) and the net dispersion is given by = ₁ + ₂ = A₁( _ v1 - _ r1 ) + A₂( _ v2 - _ r2 ) . By appropriately choosing the angles A₁ and A₂ and placing the prisms in opposite orientations (one inverted with respect to the other), we can achieve the following conditions: 1. Deviation without dispersion (Achromatic combination): The condition for zero net dispersion is = 0 , which gives A₁( _ v1 - _ r1 ) = -A₂