If a glass prism is dipped in water, its dispersive power

Dispersive power of a prism  ω=μV−μRμy−1   (when prism is in air)When outside medium is changed to water, new dispersive power is given by ωnew=μVμw−μRμwμyμw−1 = μV − μRμy − μw   Hence dispersive power increases when prism is dipped in water.