Two beams of red and violet colours are made to pass separately through a prism of $A=60^{\circ}$. In the minimum deviation position,the angle of refraction inside the prism will be

In the visible region, the dispersive powers and the mean angular deviations for crown and flint glass prisms are $\omega, \omega^{\prime}$ and $d, d^{\prime}$ respectively. The condition for obtaining dispersion without deviation, when the two prisms are combined, is:

The refractive index of the material of a prism is $\sqrt{2}$ and the angle of the prism is $30^{\circ}$. One of the two refracting surfaces of the prism is made a mirror inwards,by silver coating. $A$ beam of monochromatic light entering the prism from the other face will retrace its path (after reflection from the silvered surface) if its angle of incidence on the prism is (in $^{\circ}$)

If a thin prism of glass is dipped into water,then the minimum deviation (with respect to air) of light produced by the prism will be: $\left( {_a{\mu _g} = \frac{3}{2} \text{ and } _a{\mu _w} = \frac{4}{3}} \right)$

$A$ light ray is incident at an angle of $60^o$ on a prism of angle $45^o$. When the light ray emerges from the other surface at $90^o$ to the surface,the refractive index of the material of the prism $\mu$ and the angle of deviation $\delta$ are given by:

$A$ spectrum is formed by a prism of dispersive power $\omega$. If the angle of deviation is $\delta$,then the angular dispersion is