Photometric lighting is enabled, and American or International lighting units is set.
This name appears in the Properties and Lights in Model palettes.
You can continue to specify properties by entering options, or you can exit and set properties interactively. When you use the interactive method, you can see the results of your changes as you work.
Select the light and use grip editing to modify the light. You can also right-click the light and then click Properties to modify the properties of the light in the Properties palette.