Evaporation will be the slowest in a glass of water kept in a room because it is kept under shade and it does not receive direct sunlight. Though during daytime all the surrounding of a room get heated up, so the warm air provides heat for evaporation of water in the room but it occurs at the slowest speed. A tray of water, kept in sunlight, a kettle of water kept on a burner and a bucket of water kept on rooftop get evaporated more quickly because they receive heat directly from sunlight and burner.